AHS Online Subscription Resources
Offers an amazing array of links to English and foreign language dictionaries as well as specialized dictionaries.
Has been providing authoritative answers to all kinds of factual questions since 1938—first as a popular radio quiz show, then starting in 1947 as an annual almanac, and since 1998 on the Internet.
Thinkmap Visual Thesaurus
An interactive dictionary and thesaurus which creates word maps that blossom with meanings and branch to related words.