Wordnick All the Words “Our goal is to show you as much information as possible, as fast as we can find it, for every word in English, and to give you a place where you can make your own opinions about words known.”
Urban Dictionary “Urban Dictionary is the dictionary you wrote. Define your world 4,804,992 definitions since december 9, 1999.”
The Free Dictionary Look for a lot of words in a lot of dictionaries. Including onther languages
OneLook ® Dictionary Search Look for a lot of words in a lot of dictionaries.
YourDictionary.com The Last Word in Words Some 1800 dictionaries with more than 250 languages.
infoplease ® This site has several basic almanacs and dictionaries.
Hypertext Webster Gateway “...provides a point-and-click client interface (for non-linemode browsers) for accessing various dictionary services on the Internet.”
Phrase Finder The site contains 5,000 phrases. The search works like a phrases thesaurus. Provide a single word and it will return a list of phrases and sayings that are related to the word.
Thesaurus.net Synonyms and antonyms and also provides rhymes, quotes and idioms
Roget's Thesaurus A public-domain (1911) edition of Roget's Thesaurus
Travlang Translate travel words and phrases to foreign languages.