Wordnet

Wordnet is a database of lexical relations.

...a semantic lexicon for the English language. It groups English words into sets of synonyms called synsets ... and records the various semantic relations between these synonym sets. ... produce a combination of dictionary and thesaurus [Wikipedia].

Elements of WordNet:

synset — set of words that are synonyms in some context(s)
hypernym — Y is a hypernym of X if ∀X, X is a kind of Y
hyponym — Y is a hyponym of X if ∀Y, Y is a kind of X
holonym — Y is a holonym of X if X is a part of Y
meronym — Y is a meronym of X if Y is a part of X

Examples

Nouns

hypernym — vehicle is a hypernym of car, bus, plane, boat
hyponym — car, bus, plane, boat are all hyponyms of vehicle;
cash is a hyponym of exchange medium
holonym — car is a holonym of wheel
meronym — branch is a meronym of tree

Verbs

hypernym — move is a hypernym of walk, fly, etc.
(Some do not believe the term applies to verbs.)
troponym — walk, fly are troponyms of move; charge is a troponym of purchase
(In pure OO-design terminology, one could view troponymy as identical to hyponymy; i.e., if one did not distinguish different kinds of classes and derivations therefrom.)

Local Documentation

Prolog ancillaries:

Example using WordNet's Prolog files

Applications