http://www.m-w.com
2. travlang's Translating Dictionaries
http://www.travlang.com
3. dictionary.com
http://www.dictionary.com
4. SpellWeb
http://www.spellweb.com
5. yourDictionary.com
http://www.yourdictionary.com
6. One Look Dictionaries
http://www.onelook.com
7. My Virtual Reference Desk
http://www.refdesk.com
8. LOGOS Dictionary
http://www.logos.it
9. WebSter's Dictionary
http://www.goldendome.net
10. The Library Of Congress Thesauri
http://www.loc.gov