Big collection, but not very broad. The Acronym Finder is a searchable database of more than 100,000 acronyms, abbreviations and meanings. Not searchable, but most acronyms are linked to relevant websites. Lots of animated GIFs. A small, but very specialized reference.
Most terms have source citations.
Includes links to similar sites. The source for acronyms and abbreviations. A comprehensive guide to acronyms, etc, dictionaries on the web. This large reference allows you to search for either expansions of an acronym or acronyms containing a particular word. Help build the largest human-edited directory on the web.