BuzzWhack buzzword-compliant dictionary provides definitions for business buzzwords, slang, and jargon. http://www.buzzwhack.com/

Double-Tongued Word Wrester Records words as they enter and leave the English language, focusing on slang, jargon, and other niche categories which include new, foreign, hybrid, archaic, obsolete, and rare words. http://www.doubletongued.org/

English-to-American Dictionary ever wondered how to snog? What sort of blokes pull birds? For Americans learning Scottish English. http://www.english2american.com/

The Nonsensicon Non existent words and their meaning. http://www.nonsensicon.com/

Online Dictionary of Playground Slang indexed dictionary of colloquialisms and slang words (past and present) used throughout the English-speaking world. http://www.odps.org/

Rap Dictionary resource for hip-hop slang. http://www.rapdict.org/

SlangSite.com dictionary of slang, webspeak, made up words, and colloquialisms. http://www.slangsite.com/

Urban Dictionary define your world and submit words for others to see. http://www.urbandictionary.com/

Carleton County Colloquialisms Dictionary of the colloquial language of Carleton County, New Brunswick, Canada and Aroostook County, Maine, USA. Audio clips accompany each entry. http://www.dooryard.ca/

London Slang Online word and phrase dictionary of Cockney rhyming slang. Also includes examples of film slang. http://www.londonslang.com/

The New American Sub-Standard Politically Incorrect Dictionary A glossary of offensive terms or terms with offensive meanings. http://www.americansubstandard.com/

Slang Search Definitions of common words in English-language slang, organized by subject area. http://www.slangsearch.com/