threesome vs three

threesome and three both are nouns.

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

As nouns, threesome and three are synonyms defined as:

threesome and three: 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, tierce, trey, triad, trine, trinity, trio, triplet, troika.

threesome (noun)	three (noun)
three people considered as a unit	one of four playing cards in a deck having three pips
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

threesome (adjective)	three (adjective)
	being one more than two