WordNet

JWNL (Java WordNet Library) - A Java API for accessing the WordNet relational dictionary. Free download, support and background information.
WordNet - A Lexical Database for English - Nouns, verbs, adjectives and adverbs are organized into synonym sets, each representing one underlying lexical concept.
WordNet Perl Module - Perl OO interface to George Miller's WordNet database.
WordNet Python Module - Python interface (by Oliver Steele) to WordNet database created by George Miller.

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