WordNet - Словарь английского языка.
  11 MB | Mac OS X 10.1 or later. | Freeware

WordNet is a powerful online lexical reference system (it's a dictionary and much much more) developed at Princeton University's Cognitive Science Laboratory under the direction of Professor George A. Miller.

Mac OS X version developed by William Taysom.

Developed at Princeton University's Cognitive Science Laboratory under the direction of Professor George A. Miller, WordNet is not only an online dictionary but also a lexical reference system.