Macmillan Dictionary
www.macmillandictionary.com
A new online dictionary from Macmillan
Oxford Advanced
Learner's Dictionary
http://www.oup.com/oald-bin/web_getald7index1a.pl
The Oxford Advanced Learner's Dictionary (OALD) online
Cambridge Dictionaries Online
http://dictionary.cambridge.org/
The Cambridge Advanced Learner's Dictionary (CALD) online
Longman Dictionary of Contemporary English
Online
http://www.ldoceonline.com/
Online version of the Longman Dictionary of Contemporary English
Dictionary.com
http://www.dictionary.com
Tools including a general English dictionary, a thesaurus and an encyclopedia
online
Online dictionary and translation
service
http://www.dictionarylink.com/
A dictionary with a translation service included