Call number

Call number

A call number or pressmark is a mark consisting of characters labeled on a book. It is used to indicate shelf location. Often is the call number identical with a classification code used as a retrieval tool to identify relevant documents in the library catalog. For example may the Dewey Decimal Classification (DDC) system be used for both shelf arrangement and information retrieval purposes. The class mark in DDC is thus used as call number.

The address of a web-page (the URL) may be compared to a call-number (cf., Uniform Resource Identifier).

The term "call number" is used with a different meaning in computer programming.