Synonyms for Tierce (same or very similar meaning)
WordNet sense 1 (the third canonical hour; about 9 a.m.):
terceWordNet sense 2 (the cardinal number that is the sum of one and one and one):
leash, ternary, three, trey, triad, trinity, trio, triplet, troika, deuce-ace, III, tercet, ternion, terzetto, trineWordNet sense 3 (one of three equal parts of a divisible whole):
third, one-thirdFrom the ODE community, based on WordNetadd/edit