synset
A set of one or more synonyms that are interchangeable in some context without changing the truth value of the proposition in which they are embedded.
The basic object in WordNet is a set of strict synonyms, called a synset. By definition, each synset a word appears in is a different sense of that word.
Where it comes from
Clipping of synonym set, coined in the context of the WordNet project.
Adapted from the Wiktionary entry synset (CC BY-SA 4.0).