MARC is an acronym for MAchine-Readable Cataloging.  The five MARC 21 communication formats, Bibliographic Data, Authority Data, Holdings Data, Classification Data, and Community Information, are widely used standards for the representation and exchange of bibliographic, authority, holdings, classification, and community information data in machine-readable form.

Each MARC format provides detailed field descriptions and guidelines for applying the defined content designation and identifies conventions to be used to insure input consistency.

See also:

Bibliographic Data Format:  Introduction