1. AllWords.com

Features two modern English dictionaries, multilingual search, and translation. Also features a guide to language sites on the web and a language discussion forum.

http://www.allwords.com/

2. Cambridge International Dictionaries

Free online dictionary from Cambridge University Press.

http://dictionary.cambridge.org/

3. Cooldictionary.com

Free edition of a complete Webster dictionary. Fully crosslinked.

http://www.cooldictionary.com/

4. DICT Development Group

A WWW interface to several freely available on-line dictionaries, including Webster's 1913, the Jargon File, the US Gazetteer, and Easton's Bible Dictionary.

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

5. Dictionary Building Software for Reporters

Software program for realtime reporters and captioners that lists many diverse vocabulary lists.

http://www.dictionaryjumpstart.com/

6. Dictionary of Comprehension

A Dictionary of Comprehension in different languages.

http://www.dictionarydictionary.com/

7. Dictionary of Difficult Words

Search or browse this dictionary of more than 13,000 words.

http://www.tiscali.co.uk/reference/dictionaries/difficultwords/

8. Merriam-Webster OnLine

A free, searchable on-line dictionary and thesaurus, word games, a word of the day, and many other English language and vocabulary reference tools and resources.

http://www.merriam-webster.com/

9. OneLook Dictionaries

Look up a word or term in an Internet dictionary or glossary. Free search access to a frequently updated database of words, terms, names, and acronyms.

http://www.onelook.com/

10. online English dictionary

A free online easy to use English dictionary, well organized and arranged alphabetically.

http://www.meaningof.ca/

11. The Century Dictionary Online

Free 500,000 word dictionary of English with an encyclopedia and world atlas. Uses DjVu and JPEG formats to display page images. Has headword lookup and full text search of 22 million words of underlying text.

http://www.global-language.com/CENTURY/