threesome vs ternion

threesome and ternion both are nouns.

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

As nouns, threesome and ternion are synonyms defined as:

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

threesome (noun)	ternion (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