Urban Dictionary

It's been around for a couple of years, but it has sure grown since then! Urban Dictionary is an open source Wiki, so the latest words come from all over the world.

• "The open source glossary of slang."
  
• "A cultural reference."
  
• "The online repository of every piece of slang, jargon and cultural flotsam not listed in the library copy of Webster's."
  
• "From "cool" to "crunk," "dude" to "diggity," "shit" to "shizzle," this website assists those who need a little knowledge dropped on their slang."
  

Their self-description:

"The Urban Dictionary is a slang dictionary with words contributed by users. By soliciting contributions from the community, the Urban Dictionary is much more timely than printed dictionaries."

From Lockergnome's review (July 2003):

"If you get sued for "bad language," go to the urban dictionary to save the day. Sounds silly? It actually came to play in a court case relating to rap lyrics. The judge in the case referred to the Urban Dictionary to get the meaning of slang words. The case was dismissed. Parents who can't understand their teens' talk can use this to find out what they're up to when they use slang."