threesome vs gathering

threesome and gathering both are nouns.

Word	Noun	Adjective	Verb	Adverb
threesome	Yes	No	No	No
gathering	Yes	No	No	No

As nouns, gathering is a hypernym of threesome; that is, gathering is a word with a broader meaning than threesome:

Other hypernyms of threesome include assemblage.

threesome (noun)	gathering (noun)
three people considered as a unit	the social act of assembling
the cardinal number that is the sum of one and one and one	the act of gathering something
	sewing consisting of small folds or puckers made by pulling tight a thread in a line of stitching
	a group of persons together in one place