WordNet
WordNet is a semantic net for the English language. It groups English words into sets of synonyms called synsets, and records the various relations between these synonym sets. The purpose is twofold: to produce a more intuitively usable dictionary/thesaurus, and to support automatic text analysis and artificial intelligence applications. The database and software tools have been released under a BSD style licence and can be downloaded and used freely. The database can also be browsed online, with a somewhat limited set of features.
WordNet was created and is being maintained at the Cognitive Science Laboratory of Princeton University under the direction of psychology professor George A. Miller. Development began in 1985. Over the years, the project received about $3 million of funding, mainly from government agencies interested in automatic translation.
Database contents
The database contains about 140,000 words organized in over 70,000 synsets and distinguishes between nouns, verbs, adjectives and adverbs on the assumption that these are stored differently in the human brain. Every synset contains a group of synonymous words and a definition; a typical example is
- good, right, ripe -- (most suitable or right for a particular purpose; "a good time to plant tomatoes"; "the right time to act"; "the time is ripe for great sociological changes")
Every synset is connected to other synsets via a number of relations. These relation vary based on the type of word:
- Nouns
- synonyms: synsets with similar meaning
- hypernyms: Y is a hypernym of X if every X is a (kind of) Y
- hyponyms: Y is a hyponym of X if every Y is a (kind of) X
- coordinate terms: Y is a coordinate term of X if X and Y share a hypernym
- 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
- Verbs
- synonyms
- hypernym: the noun Y is a hypernym of the verb X if the activity X is a (kind of) Y
- coordinate terms: those verbs sharing a common hypernym
- Adjectives
- synonyms and related nouns
- antonyms: adjectives of opposite meaning
- Adverbs
- synonyms and root adjectives
- antonyms
In addition, WordNet provides a familiarity score for every word, calculated based on the number of synsets containing the word.
The hypernym/hyponym relationships among the noun synsets can also be used as an ontology in the computer science sense.
Related projects
The project EuroWordNet has produced linked WordNets for several European languages; these are not freely available however. The Global Wordnet project attempts to coordinate the production and linking of wordnets for all languages. The publishers of the Oxford English Dictionary have voiced plans to produce their own online WordNet.
See also:
External links:
- The Wordnet Home Page: http://www.cogsci.princeton.edu/~wn/
- Global Wordnet: http://www.globalwordnet.org/