threesome vs tercet

threesome and tercet both are nouns.

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

As nouns, threesome and tercet are synonyms defined as:

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

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

threesome (noun)	tercet (noun)
three people considered as a unit	the cardinal number that is the sum of one and one and one
the cardinal number that is the sum of one and one and one