access point

Description: 

A unit of information in a bibliographic record under which a person may search for and identify items listed in the library catalog or bibliographic database. Access points have traditionally included the main entry, added entries, subject headings, classification or call number, and codes such as the standard number, but with machine-readable cataloging, almost any portion of the catalog record (name of publisher, type of material, etc.) can serve as an access point. In the MARC record, most access points are found in the following fields (with XX in the range of 00-99):
1XX - Main entries
4XX - Series statements
6XX - Subject headings
7XX - Added entries other than subject or series
8XX - Series added entries
In a more general sense, any unique data element that serves as a point of entry to an organized file of information. In files indexed with controlled vocabulary, an access point may be a preferred or non preferred term.

Source: 
Reitz Joan M. (2004)