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OCLC glossary

Find a comprehensive listing of OCLC terms accompanied by definitions.

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Anglo-American Cataloging Rules, 2nd edition. An international standard for the cataloging of all types of materials collected by general libraries. AACR2 has now been superseded by RDA: Resource Description and Access.

Abbreviated records

Brief records (Encoding Level 3) that do not meet the requirements of minimal-level cataloging specifications.

Abridged edition (DDC)

A shortened version of the Dewey Decimal Classification (DDC) system that is a logical truncation of the notational and structural hierarchy of the corresponding full edition on which it is based. The abridged edition is intended for general collections of 20,000 titles or fewer. See also Full edition (DDC).


A brief summary that classifies, evaluates or describes the important points in the content of a journal article or library resource to help the reader quickly ascertain the resource's purpose. See also Full text.

Academic library

A library that is an integral part of a college, university, or other institution of post-secondary education, administered to meet the curriculum and research needs of its students, faculty, and staff.

Access keys

A combination of the Alt key and one or more alphanumeric keys, typically pressed sequentially, rather than simultaneously. Sometimes referred to as Hot keys. In the Connexion client interface, the underlined letters on menus, sub-menus, and commands (e.g., <Alt><V><U> opens the User Information window in the client). Access keys are available for all client commands.

Access method

Method used to log on to a service, download records or reports, or locate additional information. For example, a URL (Uniform Resource Locator) is used to find information on the Internet.

Access point

A name, term, code, etc., representing a specific entity that is indexed.

Accession number

An identification or inventory number assigned to an item in a library's collection. 

Account role

See Record Manager account role.

Action status

In Connexion client, an indicator in a bibliographic record that designates what actions have been taken and the outcome of each action. If taken, the following actions appear in the status bar of a displayed record: Delete Holdings, Export, Label, Produce, Submit, Replace, Report Error, Update Holdings, and Validate. 


To load an original record into the bibliographic or authority database. If using Data Sync, a record is added after Data Sync routines cannot find a match for it. The bibliographic record may not necessarily start out as an original record at the institution's end.

Added entry

A secondary access point for the resource. Added entry is a pre-RDA term.


American Library Association. The oldest and largest library association in the world. See the document About ALA for more information.

ALA character set

ALA-defined characters used in MARC records, including standard alphabetic characters, diacritics, special characters, 14 superscript characters, 14 subscript characters, and 3 Greek characters.  Also known as the MARC8 character set, these were the only characters valid in MARC records prior to the implementation of Unicode.

Allowable duplicate records

Records for the same resource, but using different cataloging languages. See also Duplicate record and Parallel records.

Anglo-American Cataloging Rules, Second edition

See AACR2.


American National Standards Institute. A nonprofit non-governmental organization composed of representatives from business and professional organizations that acts as the repository for various voluntary standards. See the document About ANSI for more information. See also ISO.

ANSI/NISO Standards for Holdings Data

Specifies display requirements for holdings statements for bibliographic resources to promote consistency in the communication and exchange of holdings information. The standard applies to holdings statements for bibliographic resources in any physical or electronic medium. It may be applied to electronic resources available to an institution, either under its control, or available under other arrangements. It applies to both manual and automated means of recording holdings.

Any qualifier

Any is the implied default qualifier in all WorldCat index searches. If you do not qualify a search, the qualifier is any.

Archive record

Prior to 2016, the bibliographic record OCLC created and stored contained local changes made by an institution to the WorldCat record. Archive records provided a complete history of an institution’s OCLC cataloging activity. OCLC used archive records to create offline products—catalog cards, magnetic tapes of records, and electronic files of records. After 2016, institutions could maintain local data in OCLC local bibliographic data (LBD) records.


An online service that provides access to detailed archival collection descriptions. It includes millions of descriptions of archival collections held by thousands of libraries, museums, historical societies, and archives worldwide.


Historical records, regardless of format, which are maintained and preserved because of their permanent legal, fiscal, regulatory, evidential, informational, or historical value. Materials that are archived are usually permanently retained.


Authority Record Number. OCLC-assigned control number for authority records in the LC names and subjects authority file.


American Standard Code for Information Interchange. A standard computer character code set, consisting of alphanumeric characters, punctuation, and a few control characters (such as a carriage return). Each ASCII character consists of 7 information bits and 1 parity bit for error checking.

Authority control

Verifies an access point in a bibliographic record against an internal or external authority file such as the Library of Congress Authority File and, if a matching authority record exists, links the access point to the corresponding authority record. If the authority record is updated, the controlled (linked) access point in bibliographic records is updated automatically.

Authority file

See OCLC Authority file.

Authority history file

Copies of all distributed Library of Congress authority file records, superseded versions of distributed records, and deleted records. Retrieve these records in Connexion client using these instructions. Retrieve these records in Record Manager using these instructions.

Authority record

A collection of information about a name (personal, corporate, family, or meeting), preferred title, or subject term (topical, geographic, genre, etc.). An authority record can contain the authorized access point, see from references, see also from references, and notes.

Authority record number

See ARN.

Authorization level

Defines a range of tasks that can be performed when logged on to a service within Connexion client. Also called authorization mode. For complete list, see the document Bibliographic Formats and Standards 5.2.1See also Record Manager account role.

Authorization number

Number assigned by OCLC to authorize use of OCLC services in Connexion client, used in conjunction with a password.

Authorization role

See Record Manager account role.

Authorized Access Point

An access point, representing an entity, formulated according to a specified standard.

Automated Request Manager

A means for libraries to define a set of automated actions the resource sharing system should perform on requests. These actions can involve sending patron-generated requests directly to lenders or having the system build a lender string and apply constant data. Library staff determine both the match criteria requests should meet to have automated actions performed as well as the actions themselves. Formerly known as Direct Request.


In WorldCat Discovery, indicates the institution from which a library resource may be obtained via Interlibrary Loan.

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Batch processing

See Batchloading.

Batch processing in Connexion client

A process of sending and completing a group or batch of searches or final actions in Connexion client. Searches may be for bibliographic or authority records and are effectively limitless (restricted only by the size of your hard drive). Using client local files (stored on the cataloger's workstation), the cataloger enters search strings and/or marks saved records for actions and then initiates batch processing. The client automatically logs onto the system, runs searches and/or performs the actions, and produces a report within the client for the results. While local records can hold a maximum of 9,999 records, Connexion users can run as many local files as desired in a single batch.

Batch search key

In Connexion client only, a search entered in command line format (full search syntax) and added to a list stored in a local file for batch processing.


A service by which records were matched and/or added to WorldCat in batches. The batchloading service was replaced by OCLC Data Sync in 2017. See also Data Sync.


Monographic Bibliographic Record Cooperative Program (BIBCO) is one of the programs of the Program for Cooperative Cataloging (PCC).  BIBCO participants contribute monographic bibliographic records in all formats to WorldCat and other international databases.  Records meet or exceed the BIBCO Standard Record (BSR) requirements and have the "pcc" code in the 042 field. See also PCC.

Bibliographic database

A file consisting of electronic entries called records, each containing a uniform description of a specific document or bibliographic item, usually retrievable by author, title, subject heading (descriptor), or keyword(s). Some bibliographic databases are general in scope and coverage; others provide access to the literature of a specific discipline or group of disciplines. A number provide full-text of at least a portion of the sources indexed. Most bibliographic databases are proprietary, available by licensing agreement from vendors, or directly from the abstracting and indexing services that create them.

Bibliographic formats

The standardized sequence, and manner of presentation of the data elements constituting the full description of a resource in a specific cataloging or indexing system. The machine-readable MARC record format has become the standard for library catalogs in many countries of the world. OCLC refers to eight bibliographic formats. In Connexion, the bibliographic formats correspond to the workforms used to create new bibliographic records. In WorldShare Record Manager, these workforms are known as material type templates. See also Books format, Computer Files format, Continuing Resources format, Maps format, Mixed Materials format, Scores format, Sound Recordings format, and Visual Materials format.

Bibliographic Formats and Standards

The guide to MARC bibliographic records in WorldCat. It provides tagging conventions, input standards, and guidelines for entering information into WorldCat. See the document Bibliographic Formats and Standards.

Bibliographic record

A description of the physical or virtual format and intellectual content of a single resource (a book, video, map, etc.) encoded in a standardized format such as MARC. 

Bibliographic Record Notification service

Commonly referred to as BibNote. See WorldCat Updates.

Bibliographic Record Processing Summary

A report that displays a summary of bibliographic and holdings actions for records in WorldCat after processing a batch of records using the OCLC Data Sync service. See also OCLC usage statistics.

Bibliographic save file

In Connexion and Record Manager, a shared online working storage area used for completing new or modifying existing WorldCat bibliographic records. In Connexion client, a local file (on your workstation or network) is also available. A limit of 9,999 records exists for either online file or local file(s).


Informal name for Bibliographic Record Notification Service. See WorldCat Updates.


See Books format.

Blank workform

The WorldShare Interlibrary Loan template for creating an interlibrary loan request, or in Connexion, a cataloging template for creating new records. Also known as blank MARC workform in Record Manager.

Book number

The part of a call number that distinguishes a specific item from other items within the same class number, also called a Cutter number. A book number is composed of letters from the author's name or letters from the title main entry and numbers. There are several systems for creating book numbers. See also Work mark.

Books format

OCLC-MARC Bibliographic format used for cataloging monographic non-manuscript language or textual material (including all published print language material, original microform publications of language material, microform reproductions of published language material, and published textual electronic resources). The three-character format designator and index qualifier for books is "BKS".

Books with feet

Library books that are commonly lost, stolen, vandalized, or misshelved. These items are usually popular titles and can cover a wide range of subjects and issues.

Boolean operators

Terms such as AND, OR, and NOT, used in Boolean logic to combine search terms. AND finds only records that contain both terms. OR finds records that contain either term. NOT finds records that contain the first term but not the second term. Combining search terms produces more precise and manageable search results.

Boolean search logic

A system of logical thought developed by English mathematician George Boole (1815-64). A Boolean search combines key concepts or search terms with operators to specify the exact information required in a database search. See Boolean operators.

Bracketed information

Descriptive information that has been provided by the cataloger added to a bibliographic record inside square brackets ([ ]).

Brief list

Default display of WorldCat search results when a Connexion search retrieves 2 to 5 records. See also Group list and Truncated list.


To scan an index for a match or the closest match to a word or phrase in records. The system matches the exact text string—character by character, from left to right—against the characters in the specified index and produces a browse list that highlights the closest match and shows the number of records for each item in the list. Clicking an entry opens the record or a record list, if multiple records match. See also Scan.

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Calendar days

WorldShare Interlibrary Loan sequential days, including weekends and holidays. See also System days.

Call number

A set of letters, numerals, or other symbols (in combination or alone) used by a library to identify a specific copy of a resource. A call number may consist of the class number; book number; and other data such as date, volume number, copy number, and location symbol. A call number indicates the relative position of the copy on the shelf, facilitating browsing.


Catalog of Art Museum Images Online. Developed by Research Libraries Group (RLG), a database of artwork images.


See Delete Holdings.


Historical term: One of the previous OCLC regional networks, formerly known as both OCLC CAPCON and then as OCLC Eastern. It was the OCLC service center for libraries in the Washington D.C.


See Circumflex.


Describes data you can enter in uppercase, lowercase, and mixed case. You do not have to match the case exactly.


Describes data you must enter exactly as it appears, matching upper- and lower-case.

Cataloging Agent mode

A Connexion authorization mode that allows the Cataloging Agent of an institution or a group to process cataloging records on a client's behalf. Agents may also process unresolved records from the group's Data Sync activity. Cataloging Agent role is also available for the WorldCat Metadata API. See also Processing center.

Cataloging In Publication

Initially a Library of Congress program, now offered by many national libraries, providing bibliographic data for new resources in advance of publication. Commonly referred to as CIP, records are created from information supplied by publishers and supplied to publishers for printing in the books. These encoding level 8 bibliographic records are available for distribution and loading into bibliographic databases. 

Cataloging Label Program

An OCLC service that lets users of OCLC cataloging products easily print labels for library materials. The free Windows software manages the creation, display, editing, and printing of pocket and spine cataloging labels.

Cataloging profile

See OCLC cataloging profile.

Cataloging source

The authority or bibliographic fixed-field element (008/39) has coded data indicating the source of the data. Abbreviations for this element differ depending upon the interface:

  • Source (Connexion authority)       
  • Srce (Connexion bibliographic)
  • Cataloging Source Code (Record Manager authority and bibliographic)

In addition, the authority and bibliographic Cataloging Source field 040 indicates the agencies that created and/or edited the record in WorldCat.

Cataloging source qualifier

Index used to limit WorldCat searches to records contributed by a specific library as identified by the library's OCLC symbol in MARC bibliographic field 040 $a or $c (example cs=OCL).


A web-based interface for copy cataloging, which can be used independently or in conjunction with a cataloging subscription for Collection Manager or Connexion.

CBS System

CBS means Centraal Bibliotheek Systeem in Dutch and translates to Central Library System in English. CBS systems have been developed as stand-alone regional and national systems.  CBS started in the 1980s in the Netherlands. CBS systems have also been implemented in Germany, France, Australia, Switzerland, United Kingdom, and Spain. CBS systems developed prior to wide-spread exchange of data and use their own data formats, such as MARC 21, UNIMARC, MAB, and PICA3, all having their own local flavor. PICA+ is the generic term for the internal data format used in CBS systems.

Character masking

See Wildcard (# or ?).


Types of dates used by publishers to identify the individual bibliographic unit of a serial, for example, date of coverage, date of publication, or date of printing.


An abbreviation referring to the Chinese, Japanese, and Korean languages and characters sets.


See Cataloging In Publication.


Also known as caret, the character (^) entered in derived searches in WorldCat to signify lack of an element to make searches more precise.  For example, in the 4,3,1 derived search for the name Jay Weitz, enter weit,jay,^ where the circumflex signifies there is no third element (middle name or initial).


A logical system for the arrangement of knowledge. 

Classification number

Often referred to as a class number, this is the part of a call number, usually a combination of letters and/or numbers, used to classify library resources by subject area using a particular classification system.

Classification system

A list of classes arranged according to a set of pre-established principles for the purpose of organizing items in a collection, or entries in an index, bibliography, or catalog, into groups based on their similarities and differences, to facilitate access and retrieval (i.e., classification by subject). Classification systems can be enumerative or hierarchical, broad or close. Examples of classification systems include Dewey Decimal Classification and Library of Congress Classification.


(1) To arrange a collection of items according to a classification system. (2) To assign a classification number to an individual work.

Click-through dialogs

Wizards in CONTENTdm that help simplify the process of entering descriptive and administrative metadata in both simple and compound records.


See Continuing Resources format.


A unique 6-character code assigned by the Chemical Abstracts Service (CAS) to identify serial and non-serial publications in all subject areas.

Collection Manager

See WorldShare Collection Manager.

Collection Sets

See WorldCat Collection Sets.


See Computer Files format.

Command line search

A type of Connexion search that allows you to type (1) any complete keyword, numeric, or derived search in a single string, including index labels, qualifiers, and Boolean operators, or (2) a browse string, including the Scan (sca) command and index label in the format sca xx:. See also Derived search.

Note: The equivalent search capability in FirstSearch, Resource Sharing, and Record Manager is called an "expert search." 

Communications format

The communications format presents a MARC record in a form that looks like one long run-on sentence, in which the fields are not preceded by tags. Immediately following the leader is a block of data called a directory. This directory tells what tags are in the record and where they are placed by a count of the characters to the position where each field begins. The directory is constructed, by computer, from the bibliographic record, based on the cataloging information, and, if any of the cataloging information is altered, can be reconstructed in the same way. See also MARC (Machine-Readable Cataloging).


When registering a shared print commitment for a published run of a serial, completeness of holdings may be evaluated and noted in a local holdings record 583 field, specifying what physical material is missing, e.g. missing foldouts, pages, issues, volumes etc. 

Computer Files format

OCLC-MARC Bibliographic format used for cataloging computer software (including programs, games, fonts), numeric data, computer-oriented multimedia, online systems or services; the three-character format designator for computer files is “COM".

Conference name

See Meeting name.


One of OCLC's integrated cataloging services, offering access to WorldCat, the OCLC Authority File, and other online databases. Connexion client is a Windows-based software interface. Both provide the same basic cataloging capabilities, though there are also unique features provided by each. A full comparison chart [] is available to help users decide which service is most appropriate for their work.


Cooperative Serials Program (CONSER, which originally stood for CONversion of SERials) is the oldest program of the Program for Cooperative Cataloging (PCC). CONSER participants contribute records for serials and integrating resources to WorldCat, where the CONSER database resides. Records meet or exceed the CONSER Standard Record (CSR) requirements and have the code "pcc" in the 042 field. See also PCC.

Constant data record

A partial record that contains standardized content for reuse in creating or editing a record without having to retype each time the content is reused. Constant data records are created by and shared among librarians at a given institution for cataloging and resource sharing activities.

Content designation

The tags, indicators, codes, and other conventions established explicitly by MARC 21 to identify and further characterize the data elements within a record and to support the manipulation of that data. MARC 21 attempts to preserve content designator consistency across formats where appropriate. See also Record structure.


OCLC's digital collection software suite. It allows you to digitize, store, search, and mount your digital objects on the Web.

Continuing Resources format

OCLC-MARC format used for cataloging resources issued over time with no predetermined conclusion. The Continuing Resources format includes serials and ongoing integrating resources. In WorldCat searches, use the Continuing Resources index (label: cnr) as a qualifier to limit results to records for this type of material.

Contract cataloging

OCLC service that catalogs libraries' collections as their cataloging agent. Formerly called TechPro or Custom Cataloging.

Control field

A 00x field. Control fields are structurally different from variable data fields containing neither indicator positions nor subfield codes. They may contain either a single data element or a series of fixed-length data elements. Although field 007 does not have indicators or subfield codes, it displays in subfielded form in Connexion interfaces.

Copy cataloging

Using an existing bibliographic record (rather than creating an original record) with edits for local use.

Copyright compliance

In Resource Sharing, copyright compliance allows borrowing libraries to provide a statement of how they conform to either US Copyright code (17 U.S. Code § 108) or local copyright code in their countries.

Corporate name

The name of an agency, association, business, firm, government, institution, nonprofit enterprise, performing group, etc. used as an authorized access point in a bibliographic record.

Corporate/Conference name derived search

See Derived search.

Course Reserves

Course Reserves is a functionality available to libraries using WorldShare Management Services and/or WorldCat Discovery that allows patrons to search for courses and view reserved materials in a library collection. Users can search for courses by name, prefix, instructor, or department.


See OCLC Customer Services Division.

Custom holdings

Customized groups of libraries managed and maintained by individual libraries to help them organize the large OCLC Resource Sharing network into smaller groups of libraries that share common characteristics.  Custom Holdings groups can be used to identify lenders for particular types of borrowing requests or to apply a deflection policy in lending, or, for Tipasa libraries, to identify Lending Priorities Groups or Proven Senders.

Custom Holdings Group record

A record that contains a list of OCLC symbols defined by an individual library either for use in identifying preferred lenders or for defining a group of libraries for deflecting lending requests in resource sharing.

Custom Holdings Path record

A record that contains one or more custom holdings group records sorted in order of borrowing preference.

Customer Service Division

See OCLC Customer Services Division.

Cutter number

A notation derived from the main entry and added to the class number to order materials within classes. Cutter numbers can be derived from the Cutter Three-Figure Author Table, the Cutter-Sanborn Three-Figure Author Table, or the OCLC Four-Figure Cutter Tables.  The notation often, but not always, combines alphabetic characters representing an author’s surname with numerals.  The class and Cutter notations together form a call number intended to be unique within a particular collection of resources.

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See Discovery to Delivery (D2D).

Data Sync

An automated service that allows synchronization of local holdings with WorldCat to make collections visible and available through OCLC services. The service adds original records to WorldCat, enhances and matches local library records with existing WorldCat records, manages local holdings data, sets or deletes holdings, and updates local bibliographic data.

Data Sync Collection Profile

The specifications for an institution's OCLC Data Sync project. The Data Sync collection profile details the general properties about the project, information about the bibliographic records, outlines local bibliographic data for retention, specifies the MARC record output if necessary, and allows for contact information and correspondence.

Data sync with output with OCLC Number

An option for an institution to elect to receive a copy of the matching OCLC MARC bibliographic record when it sets its holding symbol in WorldCat through the OCLC Data Sync service. Alternatively, the institution may choose to receive their own record(s) back.

Database enrichment

A capability that allows full and higher cataloging authorizations and cataloging roles to add such elements as subject headings, call numbers, and contents notes to WorldCat bibliographic records. Database enrichment is now part of Expert Community capabilities.

Date of entry

In FirstSearch detailed records, "Date of Entry" is the label for MARC field 008/00-05.

Also in FirstSearch, "Date of Entry" is the Advanced Search Index name (da) for OCLC-defined field 947 subfield $n and field 953 subfield $b in the ERIC database and field 953 subfield $b in the MEDLINE database.


See Discovery to Delivery (D2D).


See Digital Collection Gateway.


See Dewey Decimal Classification.


See Duplicate Detection and Resolution (DDR).

Decomposed diacritics

Two or more characters where a letter is entered first followed by one or more diacritical marks that display as one character.

For example, the base letter e (U+0065) followed by the combining acute accent (U+0301) which displays as é.

See also Diacritic and Precomposed diacritic.

Demand Driven Acquisition (DDA)

A tool that enables organizations to let their patrons drive which items are purchased by working with a vendor to set up a collection of titles available for DDA, which will trigger a purchase when a patron accesses an item via the organization's Discovery. Also known as Evidence Based Acquisition (EBA) and Patron Driven Acquisition (PDA).

Default holding library code

The holding library code is a four-character code associated with a specific OCLC symbol. It appears automatically in data fields when a user displays a bibliographic record (field 049 subfield $a) or local holdings record (field 852 subfield $b).


Deflection is a feature of such resource sharing systems as WorldShare Interlibrary Loan and Tipasa that allows the institution to say "no" to requests for items that cannot be loaned for policy and/or licensing reasons. The library is skipped in the lender string and the request moves on to the next lender. Deflection policies may be based on such factors as the request service type, local holdings, format type, OCLC profiled group membership, Custom Holding Group, maximum cost, E-license terms, and material age in years.

Delete Holdings

Action to remove an institution's OCLC symbol from a record in the database. This can be done one of two ways: Create a Delete WorldCat Holdings collection within Data Sync collections or create a Bibliographic collection with Record Status element set to "Use". Data Sync cancels the holding on the matching record when a match is found and the Record Status element (Leader byte 5) contains the character "d". This is equivalent to the Delete Holdings command in Connexion and the Delete command in Record Manager.


See Subfield delimiter.

Derive new record

For cataloging, the use of a related existing record to create a new WorldCat record.

Derived search

A shortcut type of WorldCat search using a specific number of initial characters from the words in a name and/or title. The "derived" segments of the words are separated by commas. The number and pattern of characters and commas tells WorldCat which index to search: Title (3,2,2,1); Personal name (4,3,1); Corporate/Conference name (=4,3,1); Name/Title (4,4). See also Command line search.

Detailed level information

See Holdings level.

Dewey Decimal class number

A classification number that conforms to the conventions used in the Dewey Decimal Classification system. The classes used to identify library resources are: 000, General Works; 100, Philosophy & Psychology; 200, Religion; 300, Social Sciences; 400, Language; 500, Natural Sciences & Math; 600, Applied Sciences (Technology); 700, Fine Arts; 800, Literature; 900, Geography & History.

Dewey Decimal Classification

A general knowledge organization tool conceived by Melvil Dewey in 1873 and first published in 1876. At the broadest level, the Dewey Decimal Classification (DDC) is divided into ten main classes organized by disciplines or fields of study. Together these classes cover the entire world of knowledge. See also Dewey Decimal class number.


A mark that modifies the phonetic value of some other character or characters. It is always used in conjunction with another character.

In records coded as MARC-8, each diacritic occupies its own position, directly following the modified character, although the diacritic displays correctly in relation to its character.

In records coded as UTF-8, both precomposed and decomposed diacritics may be used.

See also Precomposed diacritics and Decomposed diacritics.

Digital Archive

OCLC's CONTENTdm preservation archive service, which provides a managed storage environment for an institution's electronic content. The content is stored in the data format type and directory structure determined by the institution's local practice and collection policy, enabling the institution to get back the exact file that was submitted for archiving.

Digital Collection Gateway

A Web-based tool that enables organizations to upload the metadata of their digital content to WorldCat. It is compatible with all OAI-compliant repositories, such as CONTENTdm. The Gateway provides institutions a self-service capability to synchronize their metadata with WorldCat to give digital collections increased visibility. Institutions use the Gateway to load metadata for their digital content to WorldCat, creating profiles for the metadata to be regularly harvested, uploaded, and converted to MARC format, assigning an OCLC number to support future synchronizations.

Direct Consortial Borrowing (DCB)

See Discovery to Delivery (D2D).

Direct Request

See Automated Request Manager.


Within each MARC record, a series of fixed length entries, with one entry for each variable field (control or data) present in a record. Each Directory entry contains three portions: the field tag, the field length, and the starting character position. The Directory immediately follows the Leader at the beginning of the record.

Discovery to Delivery (D2D)

Discovery to Delivery (D2D) optimizes users’ ability to discover library resources within a consortium and to get immediate access to or request delivery of the material with little or no intervention from library staff. It also provides the tools staff need to request and track material that cannot be filled within the consortium.

Display holdings

In WorldCat Resource Sharing, a lender string may be suggested by the system based on volume and year data from the local holdings record.

For Connexion usage, see View holdings.

Document supplier

A library, agency, or commercial company that provides copies of documents on request, often for a fixed fee.

Dublin Core

An international standard that supports creation of simple, informative descriptions of electronic resources that facilitate management and discovery. The Dublin Core standard defines 15 elements for a resource description. Users can define additional elements or qualifiers for the standard elements to adapt Dublin Core to meet their needs. The standard elements provide a shared semantic framework that allows communities operating under different rules or standards to exchange metadata.

Dublin Core has as its goals the following characteristics: simple creation and maintenance, commonly understood semantics, international scope, and extensibility.

For more information, visit the official DCMI site.

Duplicate Detection and Resolution (DDR)

Software that identifies and merges duplicate bibliographic records in WorldCat. Using complex algorithms that examine data from multiple parts of each record, DDR compares some two dozen matching points to determine a similarity metric.  If the similarity is above a predetermined threshold, the records are deduplicated.  A hierarchy based on such factors as Encoding Level, codes in field 042, and the source of the cataloging selects the record to be retained.  Holdings are transferred from the deleted record to the retained record.  Under specified circumstances, some bibliographic data may transfer to the retained record.  The OCLC control number of each deleted record is added to field 019 in the retained record.  Most new and significantly edited bibliographic records are run through DDR soon after being added to or replaced in WorldCat. DDR may also target specific sets of records. See also Record matching.

Duplicate record

A bibliographic record that represents the same manifestation of a resource as another bibliographic record in the same language of cataloging. The guidelines on "When to Input a New Record," Chapter 4 of OCLC's Bibliographic Formats and Standards, define what is and what is not considered to be a duplicate record in WorldCat. See also Allowable duplicate records.

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East Asian Character Code. A set of unique 3-byte hexadecimal codes used to represent and store in machine-readable form all Chinese, Japanese, and Korean characters used in the USMARC format.

Electronic Data Exchange (EDX)

A decommissioned OCLC method of data exchange via FTP. It was a method for libraries to send and receive files.

Electronic document supplier

Document supplier that accepts WorldCat Resource Sharing requests and delivers full-text documents through messages to your library's Email system.


See Encoding Level.

Embedded holdings data

Holdings information contained in an existing MARC 21 bibliographic record rather than being in a separate local holdings record.

Enc lvl

See Encoding Level.

Encoding Level
  1. In bibliographic records, the Encoding Level represents the completeness of the record. It is identified in MARC 21 as Leader/17 and in Connexion as ELvl in the fixed fields, or in Record Manger as Encoding Level. Requirements for each encoding level in bibliographic records have varied over time. Correspondence between data in records and descriptive cataloging instructions is not exact.
  2. In authority records, the Encoding Level represents the completeness of the record. It is identified in MARC 21 as Leader/17 and in Connexion as Enc lvl in the fixed fields, or in Record Manager as Encoding Level.
  3. In holdings records, the Encoding Level represents the level of specificity of the holdings statement. It is identified in MARC 21 as Leader/17 and in Connexion and Record Manager as Encoding Level. Codes in holdings records reflect requirements of Holdings Statements for Bibliographic Items (ANSI/NISO Z39.71) and Holdings Statements-Summary Level (ISO 10324).

Enhance was a former OCLC program, established in 1983, that began the process of decentralizing responsibility for bibliographic quality control in WorldCat. Regular Enhance enabled specially authorized members of the cooperative to edit, upgrade, and replace full-level member input records in non-serial formats. National Level Enhance, instituted in 1994, enabled authorized Library of Congress catalogers and other participants in the Program for Cooperative Cataloging (PCC) to edit, upgrade, and replace full-level non-serial PCC records. Beginning in 2009, Regular Enhance was gradually superseded by the expanded editing and replacement capabilities of the OCLC Expert Community. National Level Enhance continues as the means by which PCC participants do BIBCO work in WorldCat. See also Expert Community.


A class of key conceptual objects of interest to users of information describing bibliographic data. In RDA entities include agent, collective agent, corporate body, expression, family, item, manifestation, nomen, person, place, timespan, and work.


A designation in numeric and/or alphabetic form, rather than in chronological form, presented for a serial issued in a sequence of numbering to show the relationship of the individual unit of the serial to the series as a whole. For example, Volume 235 and Volume XII are indicators of enumeration.


Historical term: A group of RLG databases. Most of the Eureka databases became part of OCLC FirstSearch.

Evidence Based Acquisition (EBA)

See Demand Driven Acquisition (DDA).

Expert Community

Beginning in 2009, the Expert Community is an expansion of the WorldCat record editing capabilities of the Enhance program to all full level cataloging users. OCLC's Expert Community provides Connexion users who have a full level authorization or higher more flexibility in making changes to WorldCat records. Maintenance of WorldCat is shared more equally between OCLC staff and member libraries. See also Enhance.

Expert search

See Command line search.


(1) A command or action that causes a record to be converted to MARC 21, MARCXML, Dublin Core, or MODS format and output to a file on a workstation or in a local system. (2) Downloading a record from WorldCat.

Export to TCP/IP connection

Export one or more bibliographic or authority records directly to a local library system via a TCP/IP port. Establishing the export connection may require configuration of the local system and firewall.


RDA defines an expression as an intellectual or artistic realization of a work in the form of alpha-numeric, musical or choreographic notation, sound, image, object, movement, etc., or any combination of such forms. See also FRBR, WEMI, Work, Manifestation, and Item.


Middleware that authenticates library users against local authentication systems and provides remote access to licensed content based on the user's authorization.

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Family name

See Surname.


Faceted Application of Subject Terminology is a faceted subject heading schema derived from the Library of Congress Subject Headings (LCSH). The facets are designed to be used in tandem, but each facet may also be used independently. The nine distinct facets are: Personal names, Corporate names, Meeting names, Geographic names, Events, Titles, Time periods, Topics, and Form/Genre.


In a bibliographic, authority, or holdings record, a tag in which the same kind of information is consistently entered. For example, bibliographic tag 245 is a field that consistently contains title information.

File structure

See Record structure.

File transfer protocol (FTP)

See FTP.

Filing indicator

In bibliographic records, determines how many initial characters the system omits before indexing the field.

Fill character

A black box or vertical bar that represents content that must have valid data, or where no attempt is made to code the data.

Final OCLC actions

Commands in the Action menu in Connexion client, to accomplish specific tasks such as adding holdings to a record, exporting a record to a local system, adding a new WorldCat record, or replacing an existing WorldCat record. In Record Manager, these commands are located on the Record and Save dropdown menus.

Actions permitted on records are determined by the authorization used.

A final action (produce, update, save, or export) must be taken on an unresolved Data Sync record in order to resolve it. See also Resolved record and Unresolved record.


OCLC FirstSearch is an online reference service with a collection of databases, full-text articles, full-image articles, library holdings, and interlibrary loan. It supports research in a wide range of subject areas with well-known bibliographic and full-text databases in addition to ready-reference tools such as directories, almanacs, and encyclopedias.

FirstSearch/ILL Direct Request Link

A link between OCLC Direct Request and the OCLC FirstSearch service that allows patrons to generate requests for materials cited in FirstSearch databases.

Fixed field

The OCLC Fixed Field consists of elements of the MARC 21 Bibliographic Leader and field 008, in addition to control fields 001 and 005. The Fixed Field may be displayed as a single area with mnemonic labels for each element or as a separate variable field in Connexion client and WorldShare Record Manager. Fixed fields, and each element within a fixed field, have a fixed length. Each element is identified by its position. Other fields with fixed length elements are 006 and 007.

Fixed-length data element

An element in a record whose length cannot be changed.

Forced add

The loading of a file of bibliographic records to WorldCat without attempting to find matching records. OCLC does a forced add rarely, when materials in the file are so unusual that the existence of matching records in the database is unlikely.


See Given name.


A standard for the representation and exchange of data in machine-readable form. There are five MARC 21 data communication formats: Authority, Bibliographic, Classification, Community Information, and Holdings. See also Bibliographic formats.


Functional Requirements for Bibliographic Records (FRBR), a 1998 publication from the International Federation of Library Associations and Institutions (IFLA).  Its intentions were “to provide a clearly defined, structured framework for relating the data that are recorded in bibliographic records to the needs of the users of those records,” and “to recommend a basic level of functionality for records created by national bibliographic agencies.”  In 2017, FRBR and its two sibling conceptual models, Functional Requirements for Authority Data (FRAD, 2009) and Functional Requirements for Subject Authority Data (FRSAD, 2010), were superseded by the IFLA Library Reference Model (LRM), developed within an entity-relationship modelling framework and designed for use in a linked data environment.

FRBR clustering

The grouping together of bibliographic records representing different but related editions of the same intellectual work, without regard to such attributes as format, language, date, and publisher, according to the model established by Functional Requirements for Bibliographic Records. See also Expression, FRBR, Item, Manifestation, WEMI, and Work.


The interval at which a continuing resource is issued. Examples include weekly, monthly, quarterly, annually, and irregularly.


File Transfer Protocol (FTP)/Secure File Transfer Protocol (SFTP) is a TCP/IP-based protocol that is generally available for file transfers to and from a large variety of hosts. FTP/SFTP is the method used to send and retrieve files.

Full edition (DDC)

The complete version of the Dewey Decimal Classification (DDC) system. See also Abridged edition (DDC).

Full-level record

A Full-level cataloging record seeks to ensure inclusion of the essential data elements necessary to meet user needs. It is a solid "floor" description of a resource that can be built upon in a shared environment. Full-level cataloging does not preclude the use of data in a bibliographic description representing more extensive cataloging treatment. Generally, full-level cataloging meets the requirements of RDA Core (RDA 1.3) or AACR2 second-level description (AACR2 1.0D2). Full-level cataloging uses ELvl codes I or blank.

Full text

The complete contents of a text-based resource, as opposed to an abstract or bibliographic record. See also Abstract.

Full text option

See Electronic document supplier.

Function keys

Keys and key combinations on the keyboard that transmit signals not associated with printable or displayable characters (examples: F1, F2, etc). In specific applications, such as OCLC Connexion, function keys are programmed to initiate commands. See also Keyboard shortcuts.

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Historical term: Group Access Capability. A group of institutions that used the OCLC system for resource sharing and interlibrary lending. A GAC had full and selective members. A selective user had access only to abbreviated bibliographic records, and only to records for its own group. Groups were composed of at least one Full member and may have included Selective members who used WorldCat Resource Sharing only. GAC could also refer to the group itself. See Profiled groups.


Historical term: Group Access Capability/Union List. The same as a GAC, but a selective user also had access to local holdings records for its group. See Profiled groups.

General retention policy

Policy for retention of a single item or parts of a continuing resource held by a library. General retention policy is coded in field 008 byte 12 of a local holdings record (LHR).  Examples include: Permanently retained, Retained for a limited period, and Not retained. See also Specific retention policy.

Given name

A name chosen for a person at birth that identifies and differentiates that person from others in the same family. Depending on the culture a person is born into, the given name can precede or follow a surname (i.e. family name). A given name may also be known as a forename, first name, or personal name. See also Surname.


Historical term: The OCLC GovDoc service, which was available to regional and selective depository libraries, provided up-to-date, MARC-format cataloging records for U.S. government documents.

Government document number

Government-assigned number for materials provided at the expense of and by the authority of any office of the government, for example, United States Superintendent of Documents (SuDoc) numbers.

Group list

In Connexion, the default display of WorldCat search results when a search retrieves 101 to 1500 records, with 1500 being the system limit for retrieval. Results in a group list are sorted by type of material and year of publication. Clicking an entry opens either a brief or truncated list, depending on the number of records represented by the group list entry. See also Brief list and Truncated list.

Group Services

OCLC service that helps libraries join to purchase, usually for a discount from the price each would pay to purchase the services on their own.

Guided entry

Edit or create a field by using system-supplied text boxes and lists to enter or change data.

Guided search

Text boxes and lists of indexes and qualifiers to enter or select the parts of a search, for example for WorldCat, LC authority, or save file records. For entering searches without having to remember indexes, labels, correct order for searches, etc., as you do for command line searches.

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Hand Press Book (HPB)

Historical term: A database that included records for European printing of the hand-press period (circa 1455-1830) from the Consortium of European Research Libraries (CERL), whose members represented national and university libraries in 16 countries, and was only available to CERL members.

Holding library

The library or collection within an institution represented by the holding library code.

Holding library code

A unique 4-character code that identifies a holding library or collection within an institution.  For 3-character OCLC symbols, the holding library is often the OCLC symbol and another character. For example ADRR, when the OCLC symbol is ADR. See also OCLC symbol and Library identifier.


The total stock of materials, print and nonprint, owned by a library or library system, usually listed in its catalog. Synonymous in this sense with library collection. In a narrower sense, all the copies, volumes, issues, or parts of an item owned by a library, especially a serial publication, indicated in a holdings statement in the record representing the item in the catalog. Holdings can be recorded in the MARC 21 Format for Holdings Information. See also Local holdings record (LHR).

Holdings display

A list of OCLC symbols of institutions that hold the item. A holdings display accompanies each bibliographic record in WorldCat.

Holdings level

There are four levels of holdings specificity, ranging from a simple statement that the library holds the resource on up to a complex, detailed statement of exactly what parts of the resource are held. For the four levels, see the document OCLC Z39.71 Local Holdings Maintenance (Table 1: Levels of Specificity).

Holdings record

A record containing the location, status, and/or copies associated with a single bibliographic item of a specific publication held by a particular institution.

Holdings symbol

See OCLC holding library code.

Hot keys

See Access keys.

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A term, number, or name used to refer to a library resource, library metadata description, or an entry within an ontology.


International Federation of Library Associations and Institutions IFLA is the leading international body representing the interests of library and information services and their users. As an independent, international, non-governmental, not-for-profit organization, IFLA aims to promote high standards of provision and delivery of library and information services, encourage widespread understanding of the value of good library and information services, and represent the interests of its members throughout the world. The Royal Library, the national library of the Netherlands, in The Hague, provides facilities for IFLA's headquarters.


See ILL Fee Management service (IFM).


Institution Holdings Bit (IHB) is represented in online displays by the OCLC symbol.


Interlibrary loan. When a library resource is unavailable in or not owned by the library, a patron may request that it be borrowed from another library. See also ILLiad, Resource sharing, Tipasa and WorldShare Interlibrary Loan

ILL Fee Management service (IFM)

A service that provides a means to reconcile  payments and charges for interlibrary loan transactions through a library's monthly OCLC invoice, eliminating individual billing.

ILL Reasons for NO report

Monthly data about Borrower and Lender activity furnished electronically at no charge. This report records the ISO-specific reason a Lender was unable to lend a requested item.


ILLiad, developed by Atlas Systems, is resource sharing management software that manages an institution’s borrowing, lending, and document delivery through a single Windows-based interface. See also ILL, Resource sharing, Tipasa and WorldShare Interlibrary Loan.


Integrated Local System. See Local system.

Import records

A command or action that causes bibliographic or authority records to be imported from a local system or offline service into the online or local save file to (1) add to WorldCat or (2) further process records received from an offline service such as WorldCat Cataloging Partners collections. The Import Records command is on the File menu in Connexion client.


A detailed alphabetical or numerical list for a specific kind of bibliographic and authority data provided by the system for retrieving a record or sets of records from a database such as WorldCat. See the document Searching WorldCat Indexes for specifics on searching bibliographic data and Indexes and indexed fields for specifics on searching authority data.

Index label

A two- or three-character code followed by a colon or equal sign that indicates to the system the index against which to match a search term in WorldCat.


Either of the first two character positions in the variable data fields that contain values which interpret or supplement the data found in the field. Indicator values are usually interpreted independently and supply information about the field for indexing and other system functions.

Initial article

Words such as a, an, the, and the non-English equivalents that are the first word in a title or corporate name. See also Nonfiling indicator.

Input Method Editor (IME)

An operating system component or program enabling users to enter East Asian language characters with a keyboard. If you install CJK languages on your workstation, Windows automatically supplies the appropriate IMEs.

Input stamp

Data appended to a call number, representing the location, copy number, or other local information for an item. Input stamps are entered within brackets in the 049 field in MARC bibliographic records.


A library, a library system, an organization, or a part of a library, library system, or organization.

Institution Holdings Bit

See IHB.

Institution profile

A term synonymous with Cataloging Profile. See also OCLC cataloging profile.

Institution record (IR)

Historical term: A bibliographic record attached to a WorldCat record that contained additional cataloging data specific to the library that contributed the IR.  Institution records were the result of incorporating "cluster" records from the RLG Union Catalog into WorldCat during the integration of Research Libraries Group (RLG) into OCLC. IRs were deleted in 2016 in favor of LBDs. See OCLC Local Bibliographic Data (LBD).

Institution symbol

See OCLC symbol.


See Integrating resource.

Integrated local system (ILS)

See Local system.

Integrating resource

A continuing resource that is added to or changed by means of updates that do not remain discrete but are integrated into the whole. Includes loose-leaf manuals that are updated by means of replacement pages, continuously updated websites, continuously updated databases, etc. The three-character format designator for integrating resources is "INT". See also Continuing Resources format, Monograph, and Serial.

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)



See Institution Record (IR).


An International Standard Book Number is a unique number assigned to a resource by its publisher. Each ISBN is a 10- or 13-digit number and has four parts: the language group of the country of publication, the publisher, the title, and the check character.


International Organization for Standardization. A name derived from the Greek word isos, meaning "equal." Founded in London in 1947 with headquarters in Geneva, ISO is a nongovernmental federation of national standardization organizations in 130 countries, dedicated to establishing international standards to facilitate commerce and cooperation in scientific, technical, and economic endeavors. The United States is represented in ISO by the American National Standards Institute (ANSI). See also ANSI.


An International Standard Serial Number consists of eight digits in two groups of four, separated by a hyphen. ISSNs are assigned through the ISSN Network and are used to identify newspapers, journals, magazines, and periodicals of all kinds and on all media.


A successive part of a serial that can be uniquely identified by words, numbers, or date of publication.


RDA defines an item as a single exemplar or instance of a manifestation. See also Expression, FRBR, Manifestation, WEMI, and Work.

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A periodical publication usually devoted to scholarly subjects.

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Keyboard shortcuts

Combinations of keystrokes that perform set actions rather than using the mouse. Also called key bindings. Most actions in Connexion either have default key bindings or can be assigned to one. See also Function keys.


A file of keystroke shortcut assignments in Connexion client. Default key assignments are provided when you first install the client. You can customize keystrokes. Keymaps command on the Tools menu used to open windows for assigning, deleting, and working with keystroke assignments.

Keyword index

Default WorldCat search index (the system searches this index if a search has no specified index). Indexes a single word in a record, but other keyword search terms or qualifiers can be combined.

Keyword search

A type of search using one or more complete words indexed in a database. The OCLC index label is "kw:".


A set of textual and/or nontextual materials in which no one material dominates and which has a collective title. For example, a workbook that comes with flashcards, worksheets, video recording, game board, playing pieces, and dice.

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Used on the spine of a book, on the pocket of a library item, or on a card representing a library item.

Label content

The types of information to be included on labels, including location, sublocation, call number, and enumeration.

Label file

A file created by catalogers that will create, edit, preview, and print labels for library resources. Connexion client has a built-in label program. Record Manager provides a My Labels service.

Language of Cataloging

Language of the cataloging agency used in those portions of the record that, according to cataloging instructions, are supplied by the cataloger. Language of Cataloging is also an index used to qualify WorldCat searches. Not the same as Language of resource.

Language of Resource

Language of the text of the resource. Language is also an index used to qualify WorldCat searches. Not the same as Language of cataloging.


See OCLC Local Bibliographic Data (LBD).


See Library of Congress.

LC call number

Identification number derived from the U.S. Library of Congress classification system. Used to collocate and retrieve library resources.


A Library of Congress Control Number (previously called a Library of Congress Card Number) is a unique number assigned to a bibliographic or authority record by the Library of Congress. Before January 2001, LCCNs consisted of a three-character prefix (often containing blanks), a two-digit year, a six-digit serial number, and a trailing blank. This number was often displayed with a hyphen separating the year and the serial number. After December 2000, LCCNs consist of a two-character prefix (often containing blanks), a four-digit year, and a six-digit serial number.


Library of Congress Rule Interpretations are cataloging guidelines issued by the Library of Congress that provide for a common practice, sometimes called "national" practice, in applying Anglo-American Cataloging Rules (AACR).  This was the practice followed by the Library of Congress and all other libraries engaged in the bibliographic enterprise. These have been superseded by LC-PCC Policy Statements (LC-PCC PS), which are issued in conjunction with Resource Description & Access (RDA) guidelines.


See Library of Congress Subject Headings.


Lightweight Directory Access Protocol is an application protocol for querying and modifying directory services running over TCP/IP.


LDR may refer to either:


Data elements that provide information for the processing of the record. The data elements contain numbers or coded values and are identified by relative character position. The leader is fixed in length at 24 character positions and is the first field of a bibliographic, authority, and holdings record.


An institution supplying the requested item through interlibrary loan to another institution.

Lender policies

Information about potential Lenders available from Directory of OCLC Members and the OCLC Policies Directory.

Lender string

OCLC symbols of up to 15 potential lenders for interlibrary loan requests.

Less-than-full-level record

See Minimal-level records.

Level I standard

The OCLC input standard establishing criteria for a full or complete bibliographic record, indicated in a MARC record as ELvl:I. Level I is the equivalent of MARC 21 encoding level blank.

Level K standard

The OCLC input standard establishing criteria for a minimal level bibliographic record, indicated in a MARC record as ELvl:K. Level K is the equivalent of MARC 21 encoding level 7.


See OCLC Local Holdings Record Summary (LHRS).

Library identifier

A locally assigned code that represents a particular institution. The code appears in a local data field of a bibliographic record submitted for Data Sync group processing. A translation table converts the library identifier to an OCLC symbol for a matched record. The OCLC symbol is set on matching records for "set holds" and removed from matched records on "cancels." See also OCLC symbol.

Library of Congress

The Library of Congress (LC) is located in Washington, D.C. and is the main research arm of the United States Congress.  It is the home of the United States Copyright Office and serves as the nation's copyright depository. Although not officially a national library, it provides services appropriate to a national library.

Library of Congress call number

See LC call number.

Library of Congress Subject Headings

An established list of preferred subject terms, curated by the Library of Congress, from which an indexer or cataloger may select when assigning subject headings to a bibliographic record representing a work he/she is cataloging. Includes main terms and subdivisions.

Local data

Data in a record that is pertinent only to the institution cataloging the record. For example, local processing information and cataloger's notes are local data. Certain 9xx fields are reserved for local data. Local data is not preserved in the WorldCat bibliographic record.

Local Data Record

See OCLC Local Data Record.

Local file

In Connexion client, the file that resides on your hard drive or a network drive at your library, not on the OCLC system. Local files are used to save bibliographic or authority records or to store bibliographic or authority constant data as you work in Connexion client. The client provides four empty default files for these purposes when you first install. You can create as many local files as you need.

Local Holdings Agent mode

A cataloging authorization level that allows an Agent to create and maintain local holdings on a member's behalf. Also known as Cataloging Agent role.

Local Holdings Format

Metadata structure used to represent or share information about a library’s collection. The MARC 21 Format for Holdings Data is an example of a local holdings format. See also MARC 21 Format for Holdings Data and OCLC Local Data Record.

Local holdings maintenance

OCLC service that allows libraries to maintain accurate, current holdings information by providing a library's holdings for materials in any format, including serials. The service supports resource sharing, collection development, circulation and acquisitions activities.

Local holdings record (LHR)

Separate holdings record attached to a related WorldCat bibliographic record that provides holdings details for a particular library. These details include: copy-specific information for an item, information peculiar to the holding library, information needed for local processing, maintenance, or preservation of an item, and version information. See also Holdings.

Local system

An institution's computer system that manages cataloging, acquisitions, circulation, serials and/or an online catalog. If elements of a local system are designed to interact, it can be called an Integrated Local System (ILS).

Local system vendor

A company that provides a library's integrated library system.


An institution, a library within an institution, a library within a group of libraries, or a collection within an institution or library where a resource is stored or held.

Locations record

See Holdings display.

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Machine-Readable Cataloging

See MARC (Machine-Readable Cataloging).

Macro recorder

A tool in Connexion client (Tools/Macros/Manage) that creates a macro by recording procedures as they are done, whether by mouse, keystroke, or a combination. The recorder creates the macro automatically in OCLC Macro Language (OML). The recorder is convenient for those who prefer not to write their own macros or lack BASIC programming skills.


Short programs that automate routine tasks in Connexion client one step at a time, using OCLC Macro Language (OML). Creating macros requires some understanding of BASIC programming language.

Magnetic tape

A strip of flexible material coated or impregnated with magnetizable particles, upon which sound, images, and/or data can be written and stored. Magnetic tape is commonly found in reel-to-reel, cartridge, or cassette form. In the context of bibliographic, authority, and/or holdings data, magnetic tape was the usual file exchange medium before such exchanges could occur via the internet.

Main entry

Under AACR2, the main entry is the primary access point for a resource.  Most commonly, it is the person or corporate body with the chief intellectual responsibility for the resource.  In other cases, the main entry is the title.

In the card catalog environment, the main entry was the card providing the most complete description of a bibliographic resource and listing all of the subject and secondary access points.

Major Microforms

See WorldCat Collection sets.


RDA defines a manifestation as a physical embodiment of an expression of a work. See also FRBR, Expression, Item, WEMI, and Work.


Items written by hand or unpublished single instance items. Examples are a handwritten or typewritten letter, a handwritten score, a hand-drawn map, etc. The handwritten or single instance characteristic distinguishes an item as a manuscript as compared to mass-produced multiple-copy publications and online resources.


See Maps format.

Maps format

OCLC-MARC Bibliographic format used to catalog cartographic material including maps, atlases, globes, digital maps, and other cartographic resources. The three-character format designator for cartographic material is "MAP".


See MARC (Machine-Readable Cataloging).

MARC-8 character sets

Approved character sets for MARC 21 cataloging as defined in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media. Subsets of Unicode. See also Non-Latin scripts and Unicode.

MARC 21 Format for Authority Data

The MARC 21 Format for Authority Data defines the codes and conventions (tags, indicators, subfield codes, and coded values) that identify the data elements in MARC 21 authority records.  It is a carrier for information concerning the authorized forms of names, titles, subjects, and subject subdivisions to be used in constructing access points, references to the authorized forms, and the interrelationships among these forms.

MARC 21 Format for Bibliographic Data

The MARC 21 Format for Bibliographic Data defines the codes and conventions (tags, indicators, subfield codes, and coded values) that identify the data elements in MARC 21 bibliographic records.  It is a carrier for bibliographic information about printed, online, and manuscript textual materials, computer files, maps, music, continuing resources, visual materials, and mixed materials. Bibliographic data commonly includes titles, names, subjects, notes, publication data, and information about the physical description of a resource. See also OCLC-MARC.

MARC 21 Format for Holdings Data

MARC 21 Format for Holdings Data defines the codes and conventions (tags, indicators, subfield codes, and coded values) that identify the data elements in MARC holdings reports for serial and nonserial resources. It is a carrier for holdings information for three types of bibliographic resources that are identified by a code in Leader/06 (Type of record). Holdings data commonly includes copy-specific information for an item, information that is peculiar to the holding organization, information that is needed for local processing, maintenance, or preservation of the item, and version information. See also Local Holdings Format and OCLC Local Data Record.

MARC (Machine-Readable Cataloging)

MARC (MAchine-Readable Cataloging) is a family of international standards for the representation and communication of bibliographic, authority, holdings, classification, and related information in machine-readable form, based upon the Format for Information Exchange, ISO 2709.  MARC standards define the three elements of record structure, content designation, and data content.  MARC 21, originally developed by the Library of Congress in the 1960s, is the most widely used of the MARC standards.  UNIMARC (Universal MARC Format), developed by the International Federation of Library Associations and Institutions (IFLA) in the 1970s, is the second most widely used MARC standard. See also Communications format.

MARC organization code

Short alphabetic codes, assigned by national agencies, representing names of libraries and other organizations that need to be identified in the bibliographic environment. They are structured and use mnemonics to help identify the institutions represented. The codes consist of as many as four subunits, usually representing geographical jurisdictions and/or the organization itself.

MARC record

A MARC record is a representation of bibliographic, authority, holdings, classification, or related data in machine-readable form that is formatted according to the appropriate MAchine-Readable Cataloging (MARC) standard and may be used for data exchange.  A single record collects data elements that describe or identify one or more units treated as one logical entity.  The record consists of a leader, a directory, and variable fields.  Variable fields are identified by a three-digit numeric tag and may include up to two numeric indicators supplying additional information about the field.  Variable fields may be further divided into subfields identified by a single-character alphabetic or numeric code.

Master record

See WorldCat record.

Material type

The type of material the record represents. The type can represent a physical type, such as atlas or kit; or content, such as biography or fiction; or focus, such as juvenile or conference publication.

Material type template

See Workform.

Materials vendor

Wholesale booksellers and publishers who provide library materials through approval plans and firm orders from institutions.

Maximum field/record size

Bibliographic records must meet size limits defined in MARC21 standards to be exported as MARC21. The number of characters a field cannot exceed is 9,999. The number of characters a record cannot exceed is 99,999. These limits apply to records exported as MARC21 using Connexion and WorldShare Record Manager. If records exceed these limits and need to be exported, the MARCXML export format must be used. The number of characters an authority record cannot exceed is 9,000.

Medical Subject Headings

The Medical Subject Headings (MeSH) thesaurus is a controlled and hierarchically-organized vocabulary used to describe the subject of a medical work. MeSH is provided by the National Library of Medicine (NLM) for medical and health sciences libraries, and includes the subject headings appearing in MEDLINE/PubMed, the NLM Catalog, and other NLM databases.

Meeting name

The name of a meeting, conference, exhibition, exposition, festival, athletic contest, scientific expedition, etc. used as an authorized access point in a bibliographic record.


See Medical Subject Headings.


Literally, data about data. It is descriptive information about a particular data set, object, or resource, including how it is formatted, and when and by whom it was collected. Originally metadata most commonly referred to digital resources, but now can refer to any physical or electronic resource. It may be created automatically using software or entered by hand.

Minimal-level records

Minimal-level records contain the essential data necessary to identify a resource. Generally, the records meet the requirements of AACR2 first-level description, rule 1.0D1. Minimal-level does not prohibit the addition of data deemed necessary.


See Mixed Materials format.

Mixed Materials format

OCLC-MARC Bibliographic format used for cataloging resources in two or more forms that are usually related by virtue of their having been accumulated by or about a person or body. Includes archival and manuscript collections of mixed forms of materials, such as text, photographs, and sound recordings. It generally excludes resources whose primary purpose is instructional. The three-character format designation for mixed materials is MIX. The mixed materials format was previously referred to as Archival and Manuscript Materials.


An aid used to help memory. Fixed field elements of records have mnemonic identifiers to help catalogers with coding and interpretation.

Mnemonic label

An abbreviated identifier for an OCLC-MARC fixed field element, constructed from the full element name that it represents.  The mnemonics are a display option in some WorldCat interfaces.  For example, the mnemonics "ELvl" or "Enc Lvl" have stood for "Encoding Level."


A resource complete in one part or intended to be complete in a finite number of parts. See also Serial.

Multipart surname

Surname that includes prefixes, hyphenated names, or names that begin with articles or prepositions.

Music publisher number

A formatted numbering designation assigned by a publisher to a music resource manifestation; these include plate numbers and publisher numbers for notated music and issue or serial numbers and matrix numbers for audio recordings. The phrase “Music Publisher Number” dates back to before field 028 was expanded for use beyond music and was still known as “Publisher Number for Music." See also Publisher number.

My Status

In Connexion client, a customized free-text note or identifier of up to 40 characters, which may be entered (Action/Set Status) or set as a default (Tools/Options/My Status), and appears in the status bar of a displayed record. My Status may be assigned to help identify, retrieve, and manage online and local bibliographic save file records and constant data and local authority save file records and constant data. It is not available for online authority save file records and constant data.

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Name Authority Cooperative Program (NACO), part of the Program for Cooperative Cataloging (PCC). Participants in NACO create and maintain authority records in the LC/NACO Name Authority File. See also PCC.

Name-Address Directory

See OCLC Policies Directory.

Name/title derived search

See Derived search.

National level enhance

See Enhance.


See NISO Circulation Interchange Protocol (NCIP).

NCIP user ID

Sequence of characters identifying the user to the responding interlibrary loan application and used as input for User authentication. Also known as User ID, account name, or login name.


National Information Standards Organization. Accredited by ANSI (American National Standards Institute) to develop voluntary technical standards for the library, information sciences, and publishing communities.

NISO circulation interchange protocol (NCIP)

NISO standard defining messaging between circulation systems, Ill systems or broker applications. This protocol is limited to the exchange of messages between and among computer-based applications enabling them to:

  • perform functions necessary to lend and borrow items
  • provide controlled access to electronic resources
  • facilitate co-operative management of these functions
NISO Standards for Holdings Data

See ANSI/NISO Standards for Holdings Data.

Non-Latin scripts

Sets of characters and symbols used to express written languages not based on the Latin alphabet.  WorldCat supports the use of all Unicode defined characters.  Non-Latin scripts include but are not limited to Arabic, Armenian, Bengali, Chinese, Cyrillic, Devanagari, Ethiopic, Greek, Hebrew, Japanese, Korean, Syriac, Tamil, and Thai. See also MARC-8 character sets and Unicode.

Non-referral days

See System days.

Nonfiling indicator

In bibliographic and authority records, indicators determine the number of character positions associated with a definite or indefinite article (e.g., An, Le, or The) at the beginning of a title that are disregarded in sorting, indexing, and filing processes. Any diacritical mark, space, mark of punctuation associated with the article, and any space or mark of punctuation preceding the first filing character is included in the count of nonfiling characters. See also Initial article.

Nongap break

In local holdings records, an indication that an apparent discontinuity in the enumeration or chronology of a continuing resource represents unpublished parts of the resource itself, not missing items. For example, a temporary cessation of publication or a change in numbering may result in a nongap break.


Institution that does not accept interlibrary loan requests through OCLC. In WorldCat holdings displays, the OCLC symbols of nonsuppliers display in lowercase letters.


Statement in the note area of the bibliographic record giving information not included elsewhere in the bibliographic description. See also Note area.

Note area

The area following the physical description in a bibliographic record giving the contents of the work, its relationship to other works, and any physical characteristics not included in preceding areas of bibliographic description. Each note is given in a separate 500-590 field(s) in a MARC record. See also Note.

Numeric search

A WorldCat search for such numeric values as the OCLC Control Number; a standard number or code that may be entirely numeric, such as a Universal Product Code (UPC); or a standard number or code that may include numeric characters, alphabetic characters, and/or punctuation, such as LC Class Numbers or CODEN Designations.

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A freely-accessible search engine for open access web resources. It was built through harvesting from open access collections worldwide using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). As of June 2021, OAIster includes more than 50 million records that represent digital resources from more than 2,000 contributors.


A nonprofit global library cooperative providing shared technology services, original research, and community programs for its membership and the library community at large. Originally "Ohio College Library Center," later "Online Computer Library Center, Inc." or "OCLC, Inc.".

OCLC Authority File

A database that documents the authoritative forms of names (personal, corporate, and family), titles, subject headings, and/or genre/form headings to be used in a catalog from the various authority files to which OCLC provides access, including, but not limited to, LC/NACO, Medical Subject Headings (MeSH), Dutch (NTA), Māori, and German (GND).

OCLC catalog card

Historical term: A 3" by 5" printed card containing bibliographic information. OCLC discontinued card production in 2015.

OCLC cataloging

OCLC's online services for cataloging library materials using WorldCat and for producing machine-readable records and other offline products. Participating institutions retrieve bibliographic records, modify the information for local use, and then set holdings. Institutions also contribute new records and location information to WorldCat for items for which no record is found. Access to cataloging activities is provided by WorldShare Record Manager or Connexion client as well as CatExpress and Z39.50 cataloging.

OCLC cataloging profile

Identifies and describes an institution's collections, including department and branch collections. Describes classification schemes and sources of subject headings. Required for using OCLC services.

OCLC control number (OCN)

OCLC control number (OCN) is a unique accession number assigned by the OCLC system when a bibliographic record is added to WorldCat. Used to search for records.

OCLC Customer Services Division (CSD)

OCLC's user assistance and support contact desk that provides support for telecommunications, hardware, and software.

OCLC-derived records

Bibliographic records originally obtained from OCLC. Some institutions export records directly from OCLC into their local system, without setting holdings online. These records are then returned to OCLC as a Data Sync collection to set and/or cancel the institution's holdings.

OCLC distributor

An authorized agent for OCLC products and services for the international market. See also OCLC regional service provider.

OCLC holding library code

A four-character code that uniquely identifies a holding library within an institution that may be based on the institution's OCLC symbol. See also OCLC symbol.

OCLC Local Bibliographic Data (LBD)

Bibliographic information that is unique to the holding library such as local subject headings, uniform titles, or notes.

OCLC Local Data Record

Describes the holdings of a specific library. Local data records may include a summary of a library’s holdings, details about the specific items in the collection, and bibliographic information that is unique for the holding library. See also Local holdings format and MARC21 Format for holdings data.

OCLC Local Holdings Record Summary (LHRS)

A concise description of all of a library’s local holdings for a specified title. Holdings summaries are most often used to provide a brief summary of a library’s serial or multipart holdings that are shelved at multiple locations.


OCLC's implementation of the MARC format. See also MARC 21 Format for Bibliographic Data.

OCLC number

See OCLC control number.

OCLC Online Union Catalog (OLUC)

See WorldCat (the OCLC Online Union Catalog).

OCLC Policies Directory

Online repository of lending and copying policies of libraries participating in WorldShare Interlibrary Loan and Tipasa. It provides a way to search resource sharing libraries by OCLC institution symbol or name and group symbol or name. It also enables institutions to enter their own information (e.g., schedule, contacts, collections, web links), informational copy and lending policies, and deflection policies that allow requests to bypass an institution. The OCLC Policies Directory replaced the Name-Address Directory as a repository for this type of information.

OCLC regional service provider

Historical term: Centers organized by region or library type in the United States. Regional networks served their libraries and library networks and provided access and support to OCLC members and participating library organizations that contracted for OCLC services. See also OCLC distributor.

OCLC symbol

A unique, alpha-numeric 3- or 5-character identifier issued by OCLC to member institutions and participants. For example OCLC symbols are used in field 040 (Cataloging Source) in bibliographic records. See also Holding library code and Library identifier.

OCLC Union List

Historical term: Former name for local holdings maintenance service. See also Local holdings maintenance.

OCLC usage statistics

Access reports on your library's use of OCLC services, including online cataloging. Available at

OCLC WorldCat Resource Sharing

See WorldShare Interlibrary Loan.


See OCLC control number.

Offline cataloging

Connexion client cataloging capabilities using local files without logging on to the OCLC system, including creating and editing records and constant data, taking immediate actions on single records or records selected from a list, and copying or moving records from one save file to another. Offline, one may also complete such local processing as exporting and printing records, printing labels, marking records with actions for batch processing, and entering batch search keys.


See WorldCat (the OCLC Online Union Catalog).

Online error reporting

Various methods of reporting errors for bibliographic and authority records are available, depending upon the system used. For information on the methods of reporting errors, please see the document Bibliographic Formats and Standards (BFAS) 5.5, Requesting changes to records.

Online Service Center (OSC)

Historical term: An online service that library administrative staff could use to order OCLC products and services, as well as view, update, or manage their OCLC account information. In 2021, ordering and invoicing were replaced by an internal system, while customer service was superseded by OCLC's Zendesk User Portal.


Online Public Access Catalog, a database composed of bibliographic records describing a library or library system's collection. Most online catalogs are searchable by author, title, subject, and keywords and allow users to print, download, or export records.

Open-ended holding

A holdings statement that indicates an item (such as a serial, a series, or a multipart work) is still in publication.

Original cataloging

Cataloging performed by an institution itself and not derived from any other source.

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Parallel records

Bibliographic records in WorldCat that describe the same resource, but which have different languages of cataloging. Cataloger-supplied descriptive cataloging fields, such as physical description and non-quoted notes, correspond to the language of cataloging (040 subfield $b). See also Allowable duplicate records and the document BFAS 2.6 Language of Cataloging.

Patron Driven Acquisition (PDA)

See Demand Driven Acquisition (DDA).


The Program for Cooperative Cataloging (PCC) consists of four programs (BIBCO, CONSER, NACO, and SACO). Libraries join this voluntary organization by becoming active in one or more of the programs. The Library of Congress houses the Secretariat of the PCC and is a PCC member. See also BIBCOCONSERNACO and SACO.


A magazine, journal, or other serial publication issued at regular, recurring intervals. Differs from a newspaper in format and publication frequency (annually, quarterly, monthly, weekly rather than daily).

Personal name derived search

See Derived search.

Phrase search

Used to search for an entire field or subfield in a record, consisting of words, numbers, or character strings. To enter a complete search string (using a "command line" search in Connexion or an "expert" search in FirstSearch, Resource Sharing, or Record Manager) use a phrase index label in the format xx=. See the document Searching WorldCat Indexes.

Physical description

Describes the physical characteristics of a library resource usually within a MARC 300 field in a bibliographic record. For books this includes such data as dimensions, number of pages, illustrations, and accompanying materials.


An acronym of Project of Integrated Cataloging Automation, PICA was originally a library cooperative in the Netherlands, serving that country as well as portions of Belgium, France, and Germany. PICA was founded with a half million seed records from OCLC's catalog in 1979. In 1999, OCLC acquired a 35% portion of PICA, increasing that share to 60% in 2000. In July 2007, OCLC acquired the remaining 40% share from the Pica Foundation.


PICA+ (or PICA plus) is the name of the internal database format based on MARC within CBS systems.


In Connexion client, a method for keeping multiple records or workforms of the same type or from the same database open simultaneously.

Policies Directory

See OCLC Policies Directory.

Post-processing report

Any number of reports generated as a result of Data Sync processing.

Precomposed diacritics

A single Unicode character that is a combined letter and diacritical mark(s) which also display as one character.

For example, the Latin small letter e with acute accent, é (U+00E9).

See also Diacritic and Decomposed diacritics.

Preferred title

A title forming the authorized access point that identifies a resource, especially if it has appeared under varying titles. Preferred titles generally serve one of two purposes: collocating versions of the resource including complete works, works in a particular literary or musical form (sonatas, songs) and distinguishing between different resources with the same or similar titles. Uniform title is the term used by AACR2, and Preferred title is the term used by RDA.

Processing center

An OCLC-defined arrangement whereby a single cataloging agent creates records or sets holdings in WorldCat under a single OCLC symbol for multiple institutions. Holding library codes identify the separate institutions. Only the OCLC symbol for the processing center appears in the holdings display of records. See also Cataloging Agent mode.

Processing report

See Post-processing report.


A structured definition of the content and format by a participating institution for many OCLC products. During the initial profiling process, OCLC assigns an OCLC symbol to an institution.

Profiled groups

Profiled Groups are set up by OCLC and used in resource sharing. Membership is based on a shared consortial or regional relationship or a set of shared policies (e.g., libraries with long lending periods, libraries who do not charge, libraries who can supply copies of e-books). These groups and their memberships are displayed in OCLC’s ILL Policies Directory. These groups can be used to build lender strings in borrowing for resource sharing or in deflection policies for resource sharing lending.


See WorldCat Cataloging Partners.


An agent responsible for publishing, releasing, or issuing a manifestation.

Publisher number

Plate and publishers' numbers for printed music (scores); serial and matrix numbers for sound recordings; videorecording numbers for visual materials, and publisher numbers other than those for sound recordings, music, or videorecordings. The publisher number is recorded in MARC field 028, subfield $a and is used for matching in Data Sync. For example, B 07042 L. See also Music Publisher number.

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Qualified searches

A means by which a database search, for instance in WorldCat or FirstSearch, may be made more precise when used in combination with numeric, keyword, or other search terms. Among the common search qualifiers are:  material type, years of publication, microform or not microform, cooperative programs, internet or not internet, language, and holding library. See also Holding library, Index label, and Material type. For more information see the document Searching WorldCat Indexes.

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See Resource Description & Access (RDA)


See Sound Recordings format.


A standardized set of related data fields retrievable as a single entity containing bibliographic, authority, or holdings information.

Within the context of OCLC Data Sync processing, a record must contain enough bibliographic data to represent a library resource.

See also Authority record, Bibliographic record, and Holdings record.

Record Manager account role

Defines a range of tasks that can be performed when logged on to a service within Record Manager. For complete list, see the document Bibliographic Formats and Standards 5.2.1. See also Authorization level.

Record matching

Within the context of WorldCat, the automated processes by which potential candidate bibliographic records are retrieved, data in the records are compared, and a best match is chosen. The methods of candidate selection, data comparison, and choice of best record vary depending upon the functions and workflows involved.  See also Duplicate Detection and Resolution (DDR) and Unique-key matching.

Record statuses

In Connexion, information stored in the working copy of a bibliographic or authority record saved in the online or local save file, usually displayed in the record's status bar and in a save file list. Statuses include actions taken and their outcomes, the origin of a record, its position in a workflow, its lock status, any customized status, etc. See also Status bar.

Record structure

In MARC 21 formats, record structure is the order in which the content designators and content appear in the record and/or file. Record structure can include technical specifications used in the record and in files. The terms record format and record structure are often used interchangeably. See also Content designation.

Record type

See Type of Record (Type).


See WorldCat registry.

Report number

A unique identifier for a publication of basic or applied research, often of a technical or scientific nature, intended to disseminate information and recommend action. In MARC bibliographic records, nonstandardized report numbers are found in field 088, whereas standardized identifiers such as the International Standard Report Number (ISRN) and the Standard Technical Report Number (STRN) are found in field 027.

Research Libraries Group

See Research Libraries Group (RLG).

Resolved record

A record that has been successfully processed through Data Sync either by matching to an existing record or adding the record as a new record in WorldCat and setting or removing the holding in addition to other possible actions. See also Final OCLC actions and Unresolved record.

Resource Description and Access (RDA)

An international standard for creating library and cultural heritage resource metadata that are well-formed according to international models for user-focused linked data applications. RDA was created by the RDA Steering Committee (RSC) to replace the Anglo-American Cataloguing Rules, 2nd Edition Revised (AACR2), which were first published in 1978. RDA continues to be developed in a collaborative process led by the RSC in line with a set of objectives and principles informed by the Statement of International Cataloguing Principles.

Resource Sharing

Activities resulting from formal or informal agreements among libraries to share collections and possibly other resources for the benefit of users. This includes the borrowing and lending of materials through interlibrary loan, facilitating the creation, sending, management, and tracking of loan requests and document orders, which may help to reduce the costs of collection development. See also ILLiad, Tipasa, and WorldShare Interlibrary Loan.

Retention commitment

The period of time that an institution commits to retaining a specific item as part of a Shared Print program. It is recorded in the 583 field of the Local Holdings Record (LHR).

Retention policy

See also General retention policy and Specific retention policy.

Review file

"Review file" itself is a historical term, although the concept remains.  Patron-generated ILL requests are currently found in the "New for Review" queue in WorldShare Interlibrary Loan and Tipasa and in the "Awaiting Request Processing" queue for ILLiad.

Research Libraries Group (RLG)

Founded in 1974 by Columbia University, Harvard University, Yale University, and the New York Public Library, RLG grew into a not-for-profit organization of more than 160 members.  Its Research Libraries Information Network (RLIN) database eventually contained some 88 million bibliographic records. In 2006, an RLG membership vote approved the combination of RLG and OCLC into a single organization. The RLIN database was integrated into WorldCat and many RLG programs and initiatives migrated to OCLC's RLG Programs, which itself evolved into the OCLC Research Library Partnership by 2011. Several OCLC products and services, including the SCIPIO database of art sales catalogs and the archival collection discovery tool ArchiveGrid, had their origins at RLG. See also ArchiveGrid and SCIPIO record.

Romanized data

Latin script representation of non-Latin script data in records.

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Subject Authority Cooperative program (SACO), one of the programs of the Program for Cooperative Cataloging (PCC). Participants in SACO submit proposals for Library of Congress Subject Headings (LCSH), for Library of Congress Classification (LCC), and for other LC vocabularies. The other vocabularies are LC Genre/Form Terms (LCGFT), LC Demographic Group Terms (LCDGT), and LC Medium of Performance Thesaurus for Music (LCMPT). See also PCC.


Standard Address Number. A unique seven-digit identifier used to signify a specific address of an organization in (or served by) the publishing industry. Initiated by R. R. Bowker, the SAN is an American National Standard.

Save file

In Connexion and Record Manager, a temporary online storage area for bibliographic or authority records that catalogers are in the process of creating, editing, reviewing, etc. Each library has a single online save file per logon authorization that is accessible to catalogers from that library only.

In the Connexion client only, catalogers can also use local save files while logged on or offline ("local" means that they are stored on a workstation or shared drive).

Online and local save files can store up to 9,999 records.

Save file number

The number the system uses to track records in your library's cataloging Save file.


Command used to send a browse string to the system to scan indexes. See also Browse.


Listings of subjects and their subdivisions arranged in a systematic order with notation given for each subject and its subdivisions, such as the series of DDC numbers 000–999, their headings, and notes.

SCIPIO record

SCIPIO (Sales Catalog Index Project Input Online) records cover art auction and rare book catalogs for sales from the late sixteenth century through the present. SCIPIO records were incorporated into WorldCat during the integration of Research Libraries Group (RLG) into OCLC. See also Research Libraries Group (RLG).


See Scores format.

Scores format

OCLC-MARC Bibliographic format used for cataloging notated music, which may consist of graphical, symbolic, or word-based musical notation in manuscript, printed, microform, or electronic form; the three-character format designator for scores is “SCO”.

Search history

In a Connexion Search WorldCat screen or window, search term input boxes have a popup or dropdown list that displays recent previous searches.

Record Manager displays recent previous searches as tabs on the left side of the screen.

Search key

See Batch search key.


See Serial.


A continuing resource issued in a succession of discrete parts, usually bearing numbering or chronological designations, that is intended to continue indefinitely. Includes annuals, journals, newspapers, numbered monographic series, periodicals, proceedings, etc. The three-character format designator for serial is "SER". See also Continuing Resources format, Integrating resource, and Monograph.

Serials format

See Continuing Resources format.


A group of separate resources related to one another by the fact that each resource bears, in addition to its own title proper, a collective title applying to the whole. The individual resources may or may not be numbered. Series may include monographic series, another type of serial, multipart monographs, and integrating resources.

A series title represents the name of a group of separate resources related to each other by subject matter, issued successively, and generally by the same publisher in a uniform style, with each resource having, in addition to its individual title, a collective series title.


Time between logon and logoff when an OCLC library is logged on to the OCLC system to use a product or service.

Set holdings on a record

OCLC member libraries "set" their holdings by attaching their OCLC symbols to bibliographic records in WorldCat. Having OCLC symbols attached to a record establishes that the institution holds the item.


See FTP.

Shared local catalog

A catalog containing the records from several libraries.

Shared Print

Programs that allow libraries to share the cost and responsibility of maintaining print collections are referred to as Shared print. Retention commitments for print resources may be registered with OCLC as part of a cataloging subscription.


Items that come to the institution from the materials vendor with labels affixed and ready to be put into the collection.

Sound Recordings format

OCLC-MARC Bibliographic format used for cataloging musical and non-musical audio recordings; the three-character format designator for sound recordings is “REC”.


See Cataloging source.

Source status

Designates the source of a displayed bibliographic record in Connexion online and local save files: Derived, Extracted, Imported, Workform, OCLC, URL. Source status is system-assigned and appears in the status bar of a displayed record.

Special character

Graphic characters and diacritics other than those used in the Latin alphabet. See the documents International Cataloging: Use Non-Latin Scripts and BFAS 2.7 Character Set for more information. See also Diacritic.

Specific retention policy

When an institution designates a general policy of limited retention for an item or parts of a continuing resource, a specific policy for that item or code may be recorded in field 008 bytes 13-15 of the Local Holdings Record (LHR). See also General retention policy.

Spine label

See Label.


See Cataloging Source.

Standard Address Number

See SAN.

Status bar

In Connexion client, shows status information at the bottom of a record or list or main client window. Stored only in the working copy of saved records, except for Report Error status. Not retained in the WorldCat record. See also Record statuses.

Stop words

Words to be omitted from a search because they are so common that they have no informational value. Stop words are not indexed and are therefore ignored by the system if entered in a search. The stop word list may vary by service and/or interface. Examples: aanandor, and the.


The smallest logical unit of information in a MARC variable field. Subfield codes (letters or numbers) identify subfields and are preceded by subfield delimiters (‡ or $). In OCLC cataloging interface displays, a subfield ‡a is implicit at the beginning of most fields, but does not display. See also Subfield delimiter.

Subfield delimiter

Character (‡ or $, depending upon the OCLC cataloging interface display) followed by a single letter or number code, used to define the beginning of a subfield within a variable field in a MARC bibliographic or authority record. See also Subfield.


The topic treated, or matter discussed, in a resource. What a resource is about. Subject schemes (for example, Library of Congress Subject Headings [LCSH]) use a controlled vocabulary to categorize library materials about the same subject.

Subject headings

A specific word or phrase that describes the subject, or one of the subjects, of a resource, selected from a list of preferred terms (controlled vocabulary) and assigned as an access point in the bibliographic record for retrieving records in a database.

A subject heading may be subdivided by the addition of subheadings (example: Libraries--History--20th century) or include a parenthetical qualifier for semantic clarification, as in Mice (Computers).

Cross-references are used to indicate semantic relationships between subject headings.

The process of examining the content of a resource and assigning appropriate subject headings is called subject analysis.

Subject scheme

Subjects categorize library material and provide controlled access to the content of resources. Schemes define concepts and relationships between concepts to support user navigation. Subject schemes, such as Library of Congress Subject Headings (LCSH), use a controlled vocabulary; that is, they use the same terms to categorize the library material about the same subject. For example, a resource about atomic structure and another resource about neutrons can have the same subject entry, Nuclear physics.


A word, character(s), or phrase that appears in conjunction with, and is subordinate to, a title proper of a manifestation. Also known as other title information.

For visual materials, a subtitle is text displayed at the bottom of a moving image expression that is a translation, transcription, or paraphrase of the dialogue or narrative.


An institution that supplies items requested via WorldShare Interlibrary Loan. The institution's interlibrary loan polices may determine what items the institution supplies via the service.


A name used as a family name that may precede or follow a given name, depending on the culture. See also Given name.

System days

In WorldShare Interlibrary Loan, days that exclude Saturdays, Sundays, OCLC-observed holidays, or other days when interlibrary loan is unavailable; also known as "Non-referral days." OCLC does not count Saturdays, Sundays, and the following as working days for aging requests:

  •        New Year's Day
  •        United States Thanksgiving Day
  •        Day after United States Thanksgiving
  •        Christmas Eve
  •        Christmas Day
  •        New Year's Eve

See also Calendar days.

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A 3-character string used to identify or label an associated MARC field. Tags are grouped numerically by function. See also Tag group.

Tag group

MARC tags beginning with and grouped by the first digit according to function. For example, 1xx tags are primary access points, 2xx tags are titles, 3xx tags are for physical description, and so on. See also Tag.


See Magnetic tape.


Transmission Control Protocol/Internet Protocol. A set of computer programs that enables communication between similar or dissimilar computers on a network. Internet Protocol is the standard for sending data on the Internet.

Terminologies Service

Historical term: A prototype service which employed library and web standards to make the terms, relationships, and other information in controlled vocabularies available as resources on the web. This functionality was largely replaced by linked data services such as those offered by LC and the US National Library of Medicine. It was officially retired in 2015, but FAST headings remain accessible. See also FAST.

Text strings

Often-used strings of text to insert into records multiple times; a shorter version of constant data. Text strings are available in both Connexion client and Record Manager. 


A cloud-based interlibrary loan management system that enables libraries to manage a high volume of requests, automate routine borrowing and lending functions, and provide an enhanced patron experience without heavy IT support, server management, or extensive configuration and training. See also ILL, ILLiadResource sharing, and WorldShare Interlibrary Loan.


A word, phrase, character, or group of characters, normally appearing on a resource, that names the manifestation or the work contained in it.

Title derived search

See Derived search.


A conversion of text from one script to another (for example, Arabic script to Latin script) that involves exchanging characters in a standardized way, such as the ALA-LC Romanization Tables.

Truncated list

In Connexion client, the default display of WorldCat search results when a search retrieves 6 to 100 records. See also Brief list and Group list.

Truncation (*)

A special character (*) entered at the end of a root term in order to search for all variations of the term or phrase. Example: librar* retrieves library as well as libraries, librarian, and librariansSee also Wildcard (# or ?).

Type of material (format) qualifier

Qualifier that limits bibliographic search results to specific formats: books (BKS), computer files (COM), continuing resources (CNR), maps (MAP), mixed materials (MIX), scores (SCO), sound recordings (REC), visual materials (VIS), etc.

Type of Record (Type)

The element in the OCLC-MARC fixed field that differentiates records created for various types of machine-readable information and specific types of material. Codes used in Type of Record (Leader/06) are also used in field 006.

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Unabridged edition (DDC)

See Full edition (DDC).


A worldwide character encoding standard allowing processing, storing, and data exchange in any language or script. Unicode includes symbols, punctuation, and other characters such as diacritics in addition to textual characters. UTF-8 (Unicode Transformation Format 8 bit) is a term often used within the MARC context to refer to Unicode. UTF-8 is a variable-width character encoding capable of encoding all valid character code points in Unicode using one to four one-byte (8-bit) code units and is the most common encoding used for the World Wide Web. See also Non-Latin scripts and MARC-8 character sets.

Uniform title

Uniform title is the term used by AACR2, and Preferred title is the term used by RDA. See Preferred title.

Union catalog

A list of the holdings of all the libraries in a library system. Also, a listing of all or a portion of the collections of a group of independent libraries, indicating by name and/or location symbol which libraries own at least one copy of each item. When the main purpose of a union catalog is to indicate location, the bibliographic description provided in each entry may be reduced to a minimum, but when it also serves other purposes, description is more complete. See also WorldCat (the OCLC Online Union Catalog).

Union list

A complete list of the holdings of a group of libraries of materials (1) of a specific type, (2) on a certain subject, or (3) in a particular field, usually compiled for the purpose of resource sharing. The entry for each bibliographic item includes a list of codes representing the libraries owning at least one copy. Union lists are usually printed, but some have been converted into online databases.

Unique-key matching

A Data Sync procedure that matches records by field 035 (OCLC control number). Also known as Numeric Search Key.

Unresolved record

A record that has failed to match any WorldCat record after being processed by the matching algorithms of OCLC Data Sync services and is added to the database via Data Sync processing as unindexed. The record is discoverable only by using the OCLC control number search. Institutions receive a report of these OCLC control numbers via an Unresolved Cross Reference File. See also Final OCLC actions and Resolved record.

Updating loose-leaf

An integrating resource that consists of one or more base volumes updated by separate pages that are inserted, removed, and/or substituted.

User profile

Defines all Connexion client settings, including those for logging on, local files, options, toolbars, customized keystroke shortcuts and text strings, session information, and more. Creating more than one user profile facilitates cataloging for more than one library (cataloging agents).


See Unicode.

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Validate a record

When cataloging, examination of the data in certain fields for consistency and compliance with various rules via the Validate command in an online interface. This may be done for authority, bibliographic, local bibliographic data (LBD), and local holdings (LHR) records. The system also performs automatic validation on records when you execute certain commands such as Replace, Produce, Update, or Delete Holdings.

Validation error

An error in the MARC format of a record as detected by OCLC system validation. Examples of validation errors include: invalid codes, tags, indicators, and subfields; missing required elements; and repetition of non-repeatable fields. 

Variable field

Any variable field other than a MARC 00x control field. Each variable data field has a tag identifier, indicators, and subfields preceded first by a delimiter (‡ or $) and then by a single letter or number subfield code. Some variable fields may occur only once in a record; others can be repeated. Length of field data is variable. MARC 21 standards require that the number of characters in a field not exceed 9,999. See also Subfield.

Varying form of title

A title or portion of the title associated with the resource recorded in the MARC 246 field. It differs from the title proper and contributes to discovery and identification of the resource.


Virtual Document eXchange, a standards-compliant interlibrary loan and document request management system initially developed by Fretwell-Downing (a company acquired by OCLC) for library groups that need greater local control of resource sharing with tight integration to local library systems. 


See Local system vendor and Materials vendor.

Vendor-provided data

Information such as barcodes, invoice numbers, invoice dates, and/or prices sent by a WorldCat Cataloging Partners vendor in a manifest that is added to the bibliographic records provided to institutions. See also WorldCat Cataloging Partners.

View holdings

Displays the list of institutional holding symbols attached to a bibliographic record; all symbols may be displayed, or they may be limited by state or region. Also known as Display holdings. In Record Manager, the list of institution holdings is part of the WorldCat holdings display.


See Visual Materials format.

Visual Materials format

OCLC-MARC Bibliographic format used for cataloging projected media, non-projected media, two-dimensional graphics, three-dimensional artifacts or naturally occurring objects, and kits; the three-character format designator for visual materials is “VIS”.

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The electronic version of the Dewey Decimal Classification (DDC) system.


An online community dedicated to the emerging technology and training needs of librarians. Originally created by the Bill & Melinda Gates Foundation's U.S. Library Program, with OCLC and other partners. WebJunction is free to all libraries to use, regardless of size, type or location.


Entities from Functional Requirements for Bibliographic Records (FRBR) that represent the products of intellectual or artistic endeavors used in RDA that stands for Work, Expression, Manifestation, Item. See also FRBR, Expression, Item, Manifestation, and Work.

Whole phrase search

All words, numbers, or character strings used to initiate a search for an entire indexed field in records. Whole phrase indexes are also browsable. See the document Searching WorldCat Indexes.

Wildcard (# or ?)

A special character used to represent one or more characters in a search term. The pound sign (#) represents a single character, and the question mark (?), alone or with a number, represents zero or more characters. Wildcards must be preceded by at least three characters in a term. Example: wom#n retrieves women or woman; col?r retrieves color or colourSee also Truncation (*).

Word search

A word, number, or character string used to initiate a search for a word in an indexed field in records. Word indexes are also browsable. See the document Searching WorldCat Indexes.


RDA defines a work as a distinct intellectual or artistic creation, that is, the intellectual or artistic content. The term work can refer to an individual work, an aggregate work, or a component of a work. See also FRBR, Expression, Item, Manifestation, and WEMI.

Work mark

The part of a book number that consists of a letter appended to the author (or biographer) designation to show the first letter of the title (or first letter of the surname of the biographer). See also Book number.

Workflow status

In Connexion client, designates a record's position in your cataloging workflow within the online or local bibliographic save file. You select from a system-supplied list: Completed, In Process (default), In Review, or New. Displays in the status bar of a record.


An OCLC-MARC template used to create an original record or local holdings record in Connexion, also known as material type template in Record Manager. The system automatically supplies some of the appropriate fields and data, depending on the format you select for the resource you are cataloging.

Working copy

A copy of the WorldCat record, displayed on the user's screen. When the user edits the working copy, the WorldCat record remains unchanged. Also called "editing locally."

WorldCat API

Provides access to WorldCat bibliographic records and holdings using the FRBR concepts to pull together various editions of the same work. The API provides access to the WorldCat databases from clients that can send RESTful URI queries with either the OpenSearch or SRU protocols and can accept RSS, Atom, MARC XML or Dublin Core® responses.

WorldCat Cataloging Partners (WCP)

A service formerly known as PromptCat that works in agreement between OCLC and library material vendors to provide copy cataloging, set WorldCat holdings, and deliver bibliographic records and spine labels for materials ordered from vendors. Cataloging partner collections are available via WorldShare Collection Manager. See also Vendor-provided data.

WorldCat Collection Sets

Historical term: A past OCLC service that enabled a library's users to quickly have access to a newly purchased set of microform, nonmicroform, or electronic content by providing a matching, precataloged set of MARC records ready to load into the library's local system. Also previously known as Major Microforms. 

WorldCat Digital Collection Gateway

See Digital Collection Gateway.

WorldCat Discovery

A cloud-based application that helps people easily find resources available at their library and in libraries worldwide through a single search. Library users and staff use their WorldCat Discovery instance to search the WorldCat database, to identify materials they need, and to see where they are available.

WorldCat holdings

See View holdings.

WorldCat knowledge base

The WorldCat knowledge base connects users to their library’s electronic content by combining data about a library’s e-resources with linking features that make the collections easier to find, share, manage and use. While managed through WorldShare Collection Manager, knowledge base data are not tied to a particular application, so libraries can streamline electronic content workflows across multiple systems. See also WorldShare Collection Manager.

WorldCat knowledge base collections

The WorldCat knowledge base is made up of vendor-neutral and cooperatively maintained collections with content from libraries and publishers around the world. The WorldCat knowledge base also includes free and open-access collections that users can find and get alongside their library’s materials. See also WorldShare Collection Manager.

WorldCat Local

WorldCat Local was replaced by WorldCat Discovery in 2019. See WorldCat Discovery.

WorldCat Navigator

An OCLC service that provides seamless resource sharing within a library consortium. The service manages returnable and nonreturnable items, and integrates with internal circulation systems and the wider OCLC resource sharing network to create a unique discovery-to-delivery service. See also Discovery to Delivery (D2D).

OCLC service that allows users to access WorldCat through a search box that can be included in a variety of web sites. Users can find the items in a library or buy them directly.

WorldCat record

The bibliographic record available to all OCLC cataloging users for copy cataloging. By policy, WorldCat contains only one WorldCat record per manifestation for each language of cataloging. Previously called the Master record, the WorldCat record does not include local data.

WorldCat registry

An online global directory of libraries, their locations, and the services they provide.

WorldCat Resource Sharing

See WorldShare Interlibrary Loan.

WorldCat (the OCLC Online Union Catalog)

An online database of records cooperatively built from the bibliographic and ownership information of OCLC contributing libraries. The WorldCat database is the largest and most comprehensive of its kind. WorldCat is the foundation of many OCLC services that enable institutions to process, manage, and share information resources, including cataloging, resource sharing, reference, discovery, collection evaluation, and local holdings. WorldCat consists of three major components: a bibliographic catalog that includes everything available to library users, a knowledge base that connects library users to electronic content, and a registry of library profiles that allows libraries to maintain information about their services. The first bibliographic records were added to WorldCat in 1971.  Until being rebranded as WorldCat in 1997, it was known as the OCLC Online Union Catalog (OLUC).

WorldCat Updates

An OCLC service available through WorldShare Collection Manager that facilitates catalog maintenance by automatically delivering updated MARC records to subscribing libraries.

WorldShare Collection Manager

OCLC cataloging tool that helps libraries streamline and automate the management of bibliographic records for their electronic and print collections in one place, while improving collection discovery and access.

WorldShare Interlibrary Loan

Service that enables OCLC libraries to borrow and lend materials quickly and securely. It facilitates creating, sending, managing, and tracking loan requests and document orders. Built on the cloud-based WorldShare platform, WS ILL is available either as a stand-alone service or fully integrated with WorldShare Management Services. See also ILL, ILLiadResource Sharing, and Tipasa.

WorldShare Record Manager

OCLC web-based cataloging tool for copy and original cataloging of individual records for physical or electronic library resources using either a MARC 21 editor or a Text View editor to access WorldCat.

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A client-server protocol established as an ANSI/NISO standard that allows the computer user to query a remote information retrieval system using the software of the local system and receive results in the format of the local system. Often used in portal and gateway products to search several sources simultaneously and integrate the results.

Z39.50 Cataloging

OCLC service that enables libraries to use the Z39.50 interface to access WorldCat to search and retrieve MARC records for cataloging, edit records in local systems, and set holding information in WorldCat.