Wordnik.com is based on the principle that people learn words best in context. Context for words includes not just traditional dictionary definitions (where ones have been written), but also example sentences for words that may not have traditional definitions yet – perfectly cromulent words like awesomepants and frolleague. Context also includes tweets from Twitter and pictures from Flickr, as well as related words (synonyms and other connected words), pronunciations, comments, tags, and how many other people have also looked up the same word.
Also, logged-in Wordniks can create their own word lists (adding to the more than 30,000 lists already available). Become a Wordnik today!