n. ~ Descriptions of materials, with each entry on a separate card (or cards), systematically arranged to facilitate access.
In a card catalog, copies of the card(s) describing the material may be filed under different headings, with separate entries for creator, title, or subject. Headings may be grouped by the type of access point, forming an author catalog, a title catalog, or a subject catalog. A catalog in which all headings are grouped in a single alphabetical sequence is described as a dictionary catalog. A card catalog may be distinguished from a card index by the amount of description. A catalog typically has enough information to help patrons assess whether the material is likely to be useful.
The use of separate cards for each item facilitated the interfiling of new or corrected entries, and the removal of obsolete entries.
Online catalogs continue to be called 'card catalogs', although such use is becoming less common.