What: wordnet
Where: http://wordnet.princeton.edu/
Description: Online lexical reference system.
A lexical database for the English language
Updated: 12/2006
Contact: mailto:[email protected]
That is, a dictionary.
There is an online version [L1 ] and an off-line version [L2 ]. The off-line version is avalable for Windows and Unix.
It is mentioned here because it is based on Tcl/Tk. Don't expect too much. It works, but is rather poorly designed.