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Library Terminology

Dictionary of common library terms.



A collection of related information (e.g., articles, abstracts, etc.) available online.


A word or phrase, usually from a controlled vocabulary, used to describe the subject and/or content of a book or article in library catalogs, indexes, abstracts, and databases.

Dewey Decimal Classification (DDC) System

A classification scheme developed in the late nineteenth century by Melville Dewey to organize library items by subject. The Dewey Decimal Classification System uses numbers ranging from 000 to 999 to represent different subject areas. Numbers following decimal places are used to further narrow subjects. Many public libraries use the Dewey Decimal Classification System.


An alphabetical list of words as well as additional information about each word (e.g., definitions, etymologies, grammatical usage, phonetic pronunciations, etc.). Dictionaries can be general or subject specific.


A systematically arranged list of people, departments, businesses, organizations, etc. Usually includes contact and/or other relevant information.


A formal, often lengthy written document that argues a particular thesis. Universities require Doctor of Philosophy Degree (PhD) candidates and some Master's Degree candidates to complete dissertations. Also referred to as a "thesis" or "treatise".

Due Date

The date by which borrowed library items must be returned.

Click a letter, then click on a word.