threesome vs trio

threesome and trio both are nouns.

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

As nouns, threesome and trio are synonyms defined as:

Other synonyms of threesome include triad, trinity.

As nouns, threesome and trio are synonyms defined as:

threesome and trio: the cardinal number that is the sum of one and one and one

Other synonyms of threesome include 3, deuce-ace, III, leash, tercet, ternary, ternion, terzetto, three, tierce, trey, triad, trine, trinity, triplet, troika.

threesome (noun)	trio (noun)
three people considered as a unit	a musical composition for three performers
the cardinal number that is the sum of one and one and one	three people considered as a unit
	a set of three similar things considered as a unit
	three performers or singers who perform together
	the cardinal number that is the sum of one and one and one