Just want to share my discovery of a wonderful DICTIONARY:

WORDWEB FREE* VERSION

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, Related words, 5000 audio pronunciations, 65 000
text pronunciations, 150 000 root words,
120 000 synonym sets, Look up words in almost any program.

WordWeb 6.3 for Windows 2000/XP/Vista/Windows 7

Free.

No SpyWare. No AdWare. No viruses. Works off-line.

http://wordweb.info/free/

--- Thunderbird 2.0.0.24 (Windows/20100228)