Semantic lexicon

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"[2] Most semantic lexicons are made up of four different "sub-nets":[2] nouns, verbs, adjectives, and adverbs, though some researchers have taken steps to add an "artificial node" interconnecting the sub-nets.

Instances are always terminal nodes because they are solitary and don’t have other words or ontological categories belonging to them.

[2] Semantic lexicons also address meronymy,[5] which is a “part-to-whole” relationship, such as keys are part of a laptop.

They are not quite as neatly hierarchical as the noun synset relations, and they have fewer tiers and more terminal nodes.

However, there are generally less terminal nodes per ontological category in adjective synset relations than that of verbs.

More generic polar adjectives such as hot and cold, or happy and sad are paired.

The most common approach is to attempt to create a shared ontology that serves as a “middleman” of sorts between semantic lexicons of two different languages.

[6] This is an extremely challenging and as-of-yet unsolved issue in the Machine Translation field.

Research has shown that every known human language has some sort of concept resembling synonymy, hyponymy, meronymy, and antonymy.

However, every idea so far proposed has been met with criticism for using a pattern that works best for English and less for other languages.

[6] Another obstacle in the field is that no solid guidelines exist for semantic lexicon framework and contents.

Orthographically, they are defined as a string of letters with spaces on either side, but semantically it becomes a very debated subject.