WordWeb — Free English thesaurus and dictionary

WordWeb is a English thesaurus and dictionary for Windows that can look up words from in almost any program.It can also look up words in web references such as the Wikipedia encyclopedia.

The database has more than 150,000 root words and 120,000 synonym sets, and plenty of proper nouns, pronunciations, and usage tags.This can really useful in finding out words while writing project reports etc.,

The licensing of this tool is different from others tools.

This is what the license says :

WordWeb free version may be used indefinitely only by people who take at most two commercial flights (not more than one return flight) in any 12 month period.

The licensing model is designed to allow relatively non-wealthy people to use the program free of charge, and to provide a small incentive for other people who fly a lot to cut down.

WordWeb – HomePage Download License

*NOTE* - It is however free-for-profit educational establishments may make a network installation of WordWeb.