Merriam-Wiki

Merriam-Webster, home of arguably the best free online dictionary and thesaurus in American English, has opened up a site for all you amateur lexicographers out there: The Open Dictionary.

Welcome to Merriam-Webster's Open Dictionary where you can 1) submit and share entries that aren't already in our Online Dictionary, and 2) browse entries submitted by other members of the Merriam-Webster Online community.

It's not precisely a wiki, of course, but it's open-participation, so it's pretty close. This should be interesting.

Merriam-Webster's Open Dictionary