英英辞書

MacMillan Online Dictionary
http://www.macmillandictionary.com/



Dictionary.com

http://dictionary.reference.com/

alphaDictionary

http://www.alphadictionary.com/index.shtml

Webster's Online Dictionary
http://www.websters-online-dictionary.org/
FreeDictionary - By Farlex
http://www.thefreedictionary.com/
OneLook Dictionary Search

http://www.onelook.com/

YourDictionary

http://www.yourdictionary.com/