triplet vs tierce

triplet and tierce both are nouns.

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

As nouns, triplet and tierce are synonyms defined as:

triplet and tierce: the cardinal number that is the sum of one and one and one

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

triplet (noun)	tierce (noun)
a set of three similar things considered as a unit	one of three equal parts of a divisible whole
one of three offspring born at the same time from the same pregnancy	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	the third canonical hour; about 9 a.m.