Free online dictionary of computing

FOLDOC is a searchable dictionary of acronyms, jargon, programming languages, tools, architecture, operating systems, networking, theory, conventions, standards, mathematics, electronics, institutions, companies, projects, products and history

covering all aspects of computing. The dictionary contains over 13500 definitions.

Entries are cross-referenced to each other and to other related resources elsewhere on the Internet. Searching is done by direct entry under terms or scrolling through letters of the alphabet.
http://foldoc.org/