tercet vs ternion

tercet and ternion both are nouns.

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

As nouns, tercet and ternion are synonyms defined as:

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

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

tercet (noun)	ternion (noun)
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