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Terminology… A


AACR2 stands for Anglo-American Cataloguing Rules, Second edition. It is published jointly by the American Library Association, the Canadian Library Association, and the Chartered Institute of Library and Information Professionals (in the UK). AACR2 is designed for use in the construction of catalogues and other lists in general libraries of all sizes. The rules cover the description of, and the provision of access points for, all library materials commonly collected at the present time. (wp)


Is a three letter acronym that in the authority world refers to the "Art & Architecture Thesaurus". It is a controlled vocabulary used for describing items of art, architecture, and material culture. The AAT contains generic terms, such as "cathedral," but no proper names, such as "Cathedral of Notre Dame." The AAT is used by, among others, museums, art libraries, archives, catalogers, and researchers in art and art history. The AAT is a thesaurus in compliance with ISO and NISO standards including ISO 2788 and ISO 5964. Final editorial control of the AAT is maintained by the Getty Vocabulary Program. (wp)

See Also [Art & Architecture Thesaurus]


See Authority Control Interest Group

Alternate Graphic Representation

The 880 tag of the bibliographic record. Representation of a field in a vernacular format (in a different script) of another field in the same record. Field 880 is linked to the associated regular field by subfield $6 (Linkage). A subfield $6 in the associated field also links that field to the 880 field. The data in field 880 may be in more than one script. (m21)

Analytical Subject Entry

Subject entry for part of a works also called subject analytics. (lcshpa)

Annotated Card Headings

Another term for Library of Congress Children’s Subject Headings. Children’s subject headings are a separate file within the LC subject file. They are designated by a second indicator of 1 in the 650 tag. (ac)


American Standard Code for Information interchange (ASCII) is a character encoding based on the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that work with text. Most modern character encodings—which support many more characters than did the original—have a historical basis in ASCII. (wp)

Author Affiliations

Part of the Table of Content Enrichment (TOC) services, Author affiliation information is gathered from the book dust jackets to further enrich your data. Typically data is added to a 9XX field of the bibliographic record. (mpg)

Authority Cleanup

Authority Cleanup is a wide variety of automated routines that update and correct individual subfields and contiguous pairs of subfields. These corrections are based on a number of subfield update files maintained by MARS 2.0 authority librarians. Routines included in this process are as follows: (mpg)

  • Update Obsolete Subdivisions
  • Correct Typographical Errors
  • Expand Abbreviations
  • Direct-to-indirect Geographic Conversions
  • Chronological Conversion
  • Delete Obsolete Subdivisions
  • Retain Selected Subdivisions
  • Correct Spacing, Capitalization, and Punctuation

Authority Control

Authority Control is a term used in library and information science to refer to the practice of creating and maintaining headings for bibliographic material in a catalog. Authority control fulfills two important functions. First, it enables catalogers to disambiguate items with similar or identical headings. For example, two authors who happen to have published under the same name can be distinguished from each other by adding middle initials, birth and/or death (or flourished, if these are unknown) dates, or a descriptive epithet to the heading of one (or both) authors. Second, authority control is used by catalogers to collocate materials that logically belong together, although they present themselves differently. For example, authority records are used to establish uniform titles, which can collocate all versions of a given work together even when they are issued under different titles. (wp)

Authority Control Interest Group (ACIG)

The Authority Control Interest Group (ACIG) was established in 1985 as a subcommittee of both the LITA and the ALCTS divisions of the American Library Association. (ALA) The charge of the ACIG committee is to provide a forum for discussion of a variety of issues related to authority control for online catalogs and for international sharing of authority data. The goals of the interest group on authority control are to raise the level of awareness on authority control issues, to encourage ideas for new approaches to authority control and to promote significant research on authority control. The committee consists of the Chair, a Secretary, and several Member at large for the following topics; Subject, Name, Uniform Title, Local Systems.

At annual and winter ALA the committee sponsors a program with a variety of speakers and topics pertaining to authority control. The program typically lasts two hours and is followed by a business meeting where current program is evaluated and topics for the next conference are determined.

If you would like to get involved in ACIG either as a committee member or as a presenter please come to the business meeting. If you are unable to attend but would be interested in being involved please visit our website for additional information. The ACIG website is at the following address: http://www.ala.org/ala/mgrps/divs/lita/litamembership/litaigs/authorityalcts/authoritycontrol.cfm

Authority file segmentation

Authority file segmentation is the segmentation of your authority records by the library’s integrated library system. Segmentation can be determined by authority type, LC, LC Children, MeSh, Canadian, or segmentation can be determined by usage, name, subject, series title. It is the library’s integrated library software that dictates file segmentation. (mpg)

Authority file source

Authority file source refers the where the automated authority control vendor is getting authority records for your master authority file. There are two sources your authority file comes from when doing automated authority control. The first is when a file is created through the automated process as each authorized bibliographic heading is matched against national headings. The source then is the matched and unmatched headings from the library’s own database. The second source is when a library has an existing authority file and the file is re-mastered to bring it into the authority vendor’s master file and updated authority records are re-distributed to the library. (mpg)

Authority Matching

The second phase of MARS 2.0 Authority Control is Authority Matching. Authority matching compares each authority controlled heading in your bibliographic records against authority record headings from any of a number of national and other authority files. Authority matching uses the headings in authority records to update or correct the bibliographic headings so they conform to current standards. A matching algorithm is used to enhance the matching process. Authorized headings and see from tracings of the national authority record are matched against to produce updated authority headings with corresponding national authority records. (mpg)

Authority Records

The most common way of enforcing authority control in a bibliographic catalog is to set up a separate index of authority records, which relates to and governs the headings used in the main catalog. This separate index is often referred to as an "authority file." It contains an indexable record of all decisions made by catalogers in a given library (or -- as is increasingly the case -- cataloguing consortium), which catalogers consult when making, or revising, decisions about headings. It is to be remembered that the function of authority files is essentially organizational, rather than informational. That is to say, they (ideally) contain a sufficient amount of information to establish a given author or title as unique, while excluding information that, while perhaps interesting to a reader, does not contribute to this goal. (wp)

Authority Record Distribution

see Authority File Segmentation

Authority Record Status

The 05 Byte of the authority leader tells what the status of the authority record is. The following codes are used to determine the status. (m21)

a - Increase in encoding level

c - Corrected or revised

d - Deleted

n - New

o - Obsolete

s - Deleted; heading split into two or more headings

x - Deleted; heading replaced by another heading

Authority update frequency

How often a library should run Notification Services in their library is based on the following.

  • Frequency—How often does your organization’s authority file need to be updated?
  • Resources—Does your organization have the staff to upload changed authority records at the frequency you chose?
  • Cost—Is frequency important enough to incur additional cost (weekly and monthly delivery are more expensive)?

Most libraries under 500,000 bib records do not need to run Notification Services more than four times a year. A good way to measure how frequent you need this service done is to compare it to how often you add bibliographic records. If you are adding about 5,000 records a quarter then both Current Cataloging and Notification Services should be run every quarter. If you are adding about 5,000 bibliographic records once a year then consider running Notification and Current Cataloging Services once a year. Backstage Library Works can establish a schedule that responds to local requirements. (mpg)

Authorized Heading (form)

Also called Established Heading, an authorized heading is the 1xx of authority record. It is the version of the heading that is to be used to represent the authority record. Variations of the authorized heading will be found in the 4xx of the authority record. An authority record in which field 100-155 contains an established name or subject. Heading refers to the form of name (or title) that the cataloguer has chosen as the form to represent this data, or the authorized form. (wp, ac, m21)

Automated Authority Control

A computer generated process that cleans up, matches and then delivers nationally recognized authority records. This process will replace (flip) existing bibliographic headings under authority control with the nationally recognized authorized heading found in the 1xx of the authority record. Both updated bibliographic headings and corresponding authority records are delivered to the library for uploading. (ac)

Auxiliary File

The MARS 2.0 Auxiliary File contains records with additional validated headings and additional cross-references not present in national authority files. The additional cross-references convert incorrect or obsolete forms to the authorized form of the headings. Authority records from this file are used during MARS 2.0 Authority Matching only and are not distributed to libraries. (mpg)

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