Dictionaries

Cambridge Dictionary http://dictionary.cambridge.org/

The American Heritage Dictionary of the English Language http://www.bartleby.com/

Wikitionary http://en.wiktionary.org/wiki/Main_Page

Free Dictionary http://www.thefreedictionary.com/

Your Dictionary http://www.yourdictionary.com/

Definitions Dictionary http://www.dict.org/bin/Dict

Merriam Webster Dictionary http://www.merriam-webster.com/

Multi lingual Dictionary http://lookwayup.com/free/Dictionary.htm

Heinle’s Newbury House Dictionary of American English http://nhd.heinle.com/home.aspx

Grandiloquent Dictionary http://www.islandnet.com/~egbird/dict/dict.htm

One look at 1062 dictionaries & A reverse dictionary http://www.onelook.com/

Wordsmyth English dictionary and Thesaurus http://www.wordsmyth.net/

English Homophone Dictionary http://www.earlham.edu/~peters/writing/homofone.htm

Medical Dictionary and abbreviations http://www.medilexicon.com/

Collins Dictionaries http://www.collinsdictionary.com/