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Concept
Semantic lexicon
Résumé
A semantic lexicon is a digital dictionary of words labeled with semantic classes so associations can be drawn between words that have not previously been encountered. Semantic lexicons are built upon semantic networks, which represent the semantic relations between words. The difference between a semantic lexicon and a semantic network is that a semantic lexicon has definitions for each word, or a "gloss".
Semantic lexicons are made up of lexical entries. These entries are not orthographic, but semantic, eliminating issues of homonymy and polysemy. These lexical entries are interconnected with semantic relations, such as hyperonymy, hyponymy, meronymy, or troponymy. Synonymous entries are grouped together in what the Princeton WordNet calls "synsets" Most semantic lexicons are made up of four different "sub-nets": nouns, verbs, adjectives, and adverbs, though some researchers have taken steps to add an "artificial node" interconnecting the sub-nets.
Nouns are ordered into a taxonomy, structured into a hierarchy where the broadest and most encompassing noun is located at the top, such as "thing", with the nouns becoming more and more specific the further they are from the top. The very top noun in a semantic lexicon is called a unique beginner. The most specific nouns (those that do not have any subordinates), are terminal nodes.
Semantic lexicons also distinguish between types, where a type of something has characteristics of a thing such as a Rhodesian Ridgeback being a type of dog, and instances, where something is an example of said thing, such as Dave Grohl is an instance of a musician. Instances are always terminal nodes because they are solitary and don’t have other words or ontological categories belonging to them.
Semantic lexicons also address meronymy, which is a “part-to-whole” relationship, such as keys are part of a laptop. The necessary attributes that define a specific entry are also necessarily present in that entry’s hyponym. So, if a computer has keys, and a laptop is a type of computer, then a laptop must have keys.
Source officielle
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