DICTIONARIES
Oxford Dictionary
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Cambridge Free English Dictionary and Thesaurus
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Merriam-Webster Online: Dictionary and Thesaurus
Macmillan Dictionary and Thesaurus
Dictionary.com
Acronym Finder
Urban Dictionary
Definations.net
Visual Thesaurus
Vocabulary.com
Medical dictionary
Crossword Dictionary
Legal dictionary
Online Etymology Dictionary
Reference.com
FOLDOC – Computing Dictionary
The free dictionary