threesome vs triplet

threesome and triplet both are nouns.

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

As nouns, threesome and triplet are synonyms defined as:

threesome and triplet: 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, trio, troika.

threesome (noun)	triplet (noun)
three people considered as a unit	a set of three similar things considered as a unit
the cardinal number that is the sum of one and one and one	one of three offspring born at the same time from the same pregnancy
	the cardinal number that is the sum of one and one and one