WordWeb is a free English thesaurus and dictionary for Windows, and can be used to look up words from within almost any program in just one click. It works off-line, but can also look up words in web references such as the Wikipedia encyclopedia. Features of the free version include: Definitions and synonyms, proper nouns, related words, pronunciations, with 150 000 root words, and 120 000 synonym sets. Finally, it allows you to look up words in almost any program.