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  and an off-line version . 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.