This is a great study tool if your looking into some Greek etymologies or studying the use of a word in philosophy. It's simple to use and also gives the authors who use the word as well as page numbers ect... Find it here: Greek word Study Tool. It uses several different reference materials for its sources.
I believe the above project was actually started over at Harvard and then tufts adopted a more user friendly approach which only included Greek. The Harvard Version is called Pollux: Archimedes Project Dictionary Access. This actually contains more information (Latin, Sumerian.....) but at least for me its harder to use.
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