American Heritage

Includes over 90,000 word entries, including pronunciation, etymology and word history.

American Sign Language

Displays an image of the ASL sings as well as a definition of the term.  Included is the basic alphabet and numbers 1-10. 

Dictionary.com

Multi-source version based on-line dictionary.

Directory of Bilingual and Multilingual Dictionaries

Lexicool.com's online dictionary search engine currently has links to over 4000 bilingual and multilingual dictionaries and glossaries freely available on the Internet. Search by language, subject or keyword.

Merriam Webster

Merriam-Webster provides a free online dictionary, thesaurus, audio pronunciations, word of the day, word games, and other English language resources.

NetLingo: The Internet Language Dictionary

Contains thousands of words and definitions that describe the online world of business, technology, and communication.  Features a listing of hundreds of words, that are rapidly evolving into the new vocabulary of the technology industry and the Web community.

Oxford Dictionary Online

Searches the Compact Oxford English Dictionary, containing 145,000 words, phrases and definitions.

Whatis.com

Hyper-linked definitions for thousands of the most current IT-related words All can be browsed or searched. Includes special sections on How the Internet Works; Writing HTML; Software; and Hardware.

Your Dictionary

A language products and services company that maintains the most comprehensive and authoritative language portal on the web with more than 2500 dictionaries and grammars in over 300 languages, games that build language skills, and a forum (The Agora) for discussing language issues with the logophile community.

Bartleby.com 
Features word definitions and a hyperlinked category index. Contains 35,000 synonyms and over 250,000 cross-references. 

Thesaurus.com 
Includes a brief definition, synonyms, antonyms and concept, the general idea underlying the terms in the entry. Arranged in dictionary style format, with over 17,000 entries 

Wordsmyth.net

Original standard dictionary-thesaurus of American English, with definitions and pronunciations, including integrated thesaurus and usage examples. 

Onelook.com

Search engine for words and phrases. More than 5 million words in more than 900 online dictionaries.