WordWeb is a one-click English thesaurus and dictionary for Windows that can look up words in almost any program. 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
5000 audio pronunciations
65 000 text pronunciations
150 000 root words
120 000 synonym sets
Look up words in almost any program
The software has a full dictionary and thesaurus for American, British, Canadian, Australian, Indian, and global English.
Changelog for this release:
Audio pronunciations, derived and confused words, extensive revisions, optional Oxford and Chambers dictionaries.