ternion vs tierce

ternion and tierce both are nouns.

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

As nouns, ternion and tierce are synonyms defined as:

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

ternion (noun)	tierce (noun)
the cardinal number that is the sum of one and one and one	one of three equal parts of a divisible whole
	the cardinal number that is the sum of one and one and one
	the third canonical hour; about 9 a.m.