Dictionaries

Webster's Online Dictionary: The Rosetta Edition - This database doubled with a metasearch tool extracts records from a variety of online and public-domain paper dictionaries, both general and specialized. It offers English definitions, as well as translations from/to a hundred languages.
http://www.websters-online-dictionary.com

Farlex Free Dictionary - Collection of dictionaries by subject including medical and legal together with free and subscription encyclopedias, in ten languages.
http://www.thefreedictionary.com/

Word Assault - Looks up multiple words simultaneously using several databases including Webster's, Easton's, Wordnet, and the Devil's Dictionary.
http://www.wordassault.com/

Research-It - Includes several dictionaries and a thesaurus as well as online tools for shipping and mailing, currency exchange, and language translation.
http://www.itools.com/

Glossaries - Collection of more than 2400 links to glossaries and dictionaries.
http://frankdietz.com/glossary.htm

Dictionary Building Software for Reporters - Software program for realtime reporters and captioners that lists many diverse vocabulary lists.
http://www.dictionaryjumpstart.com/

Dictsearch - Search a variety of dictionaries including monolingual, bilingual, and specialty dictionaries.
http://www.foreignword.com/Tools/dictsrch.htm

Dictionary Society of North America - An international organization of librarians, booksellers, translators, linguists, publishers, writers, journalists, and collectors. Founded in 1975 to further research in dictionary making, study, collection, and use. Member of the American Council of Learned Societies.
http://polyglot.lss.wisc.edu/dsna/index.html

KnowPlay? - Simple and integrated access to dictionaries, thesauri, encylopedias, and quotation databases.
http://www.kplay.cc/reference.html