Geniusfind Reference

http://www.m-w.com/thesaurus.htm - Merriam-Webster is celebrating its 150th anniversary by bringing the high-quality references you trust to the Net. Back in the 1820s, Noah Webster was on the cutting edge of American English. In 1997, Merriam-Webster carries forward his legacy into the electronic age.
http://www.yourdictionary.com/ - YourDictionary.com (YDC) was founded in 1999 to provide the world's most comprehensive, and authoritative portal for language, and language-related products and services on the world wide web. YourDictionary.com has the widest and deepest set of dictionaries on the web (more than 1500 dictionaries representing more than 230 languages).
http://www.thesaurus.com/ - Lexico LLC is a leading provider of language learning services on the Internet, including Dictionary.com, an online English Dictionary and directory of Internet reference sites, and Thesaurus.com, an online version of Roget's Thesaurus of English Words and Phrases.
http://www.bartleby.com/62/ - Bartleby.com is an innovative internet publisher providing millions of students, educators and the intellectually curious with unlimited access to books and information on the web, free of charge. They features a full-text searchable database containing over 200,000 web pages, including over 22,000 quotations and 4,765 poems. It's the most comprehensive reference site on the web, combining the best classic reference works with the best modern reference works.
http://web.cs.city.ac.uk/ - The School of Informatics offers this interface onto the Project Gutenberg Etext of Roget's Thesaurus No. Two, which is derived from the version of Roget's Thesaurus published in 1911.
http://humanities.uchicago.edu/ - The University of Chicago: Search the headwords or full text of Roget's Thesaurus, 1911, version 1.02 (supplemented: July 1991) released to the public domain by MICRA, Inc. and the Gutenberg Project. Internal cross references are represented as clickable hyper-text links.
http://www.shu.ac.uk/ - Phrase Finder - a professional writers' resource for generating ideas for headlines, advertising copy, song lyrics etc. Just give it a word and it will return a list of phrases/sayings that are related to the word in some way.
http://www.wordsmyth.net/ - The Wordsmyth Educational Dictionary-Thesaurus (WEDT) is the only online American English dictionary with an integrated thesaurus. WEDT contains 50,000 headwords, and very precisely defined and hyperlinked synonyms. The search engine allows for very flexible searching.
http://www.plumbdesign.com/thesaurus/ - The Plumb Design Visual Thesaurus is an exploration of sense relationships within the English language. By clicking on words, you follow a thread of meaning, creating a spatial map of linguistic associations. This is an interesting concept, and it's fun to watch.