ternary vs triad

ternary and triad both are nouns.

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

As nouns, ternary and triad are synonyms defined as:

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

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

ternary (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

ternary (adjective)	triad (adjective)
having three units or components or elements