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Library Terminology: O

Dictionary of common library terms.

Click a letter, then click on a word.



An abbreviation for Online Computer Library Center. The world's largest, most comprehensive bibliographic database. OCLC is used by libraries to collaborate cataloging materials, to perform reference work, and to provide a access to worldwide library holdings that Interlibrary Loan utilizes.

Online Catalog / Online Library Catalog

See Catalog.

Online Database

See Database.


An acronym for Online Public Access Catalog.

See Catalog.

Open Access (OA)

A publishing model that advocates disseminating scholarly information without restrictions.


Borrowed library items that have not been returned by their due date.


See Folio.