ternion vs triad

ternion and triad both are nouns.

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

As nouns, ternion and triad are synonyms defined as:

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

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

ternion (noun)	triad (noun)
the cardinal number that is the sum of one and one and one	a three-note major or minor chord; a note and its third and fifth tones
	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