OneLook Dictionary Search - Collects definitions from more than 100 dictionaries, ranging from garden-variety Merriam-Webster's to the Yiddish-Hebrew-English-German-Russian Picture Dictionary.

Merriam-Webster Online - Get the Word of the Day e-mailed every morning. It’s free! Add a Free Dictionary Button to Your Browser. Word Games. Thesaurus
* the Visual Thesaurus™. - Type in a word in the text box to the upper left of this window, click "look it up," and you’ll be rewarded with an interactive map showing the meaning of your word.
* yourdictionary.com - lets you search dictionaries in more than 260 languages and upwards of 100 specialties (business, law, medicine, computing, and more). Advised by leading linguistic experts, this site is invaluable both for word lovers and for those who failed junior-high...