Voycabulary Enter a URL and Voycabulary re-creates the document with every word hyperlinked. Click on a word to see its definition. Choice of languages.
Dictionaries many languages, from LINGUIST
OneLook Links to more than 500 dictionaries

General Dictionaries in English
Links to Dictionaries
Merriam Webster Collegiate Dictionary With online word games

Rhyming Dictionaries in English
Online Rhyming Dictionary WriteExpress
Semantic Rhyming Dictionary

Specialized Dictionaries
Techweb Encyclopedia
Roget's Thesaurus
Devil's Dictionary Ambrose Bierce, 1911
Net Lingo
WebSter's Dictionary HTML-aware spell-checker