THESAURUS
triad
arpeggio, broken chord, chord, clover, common chord, concento, concord, consonant chord, deuce-ace, diminished seventh chord, dominant chord, enharmonic, leash, major
triad, minor chord, set of three, seventh chord, shamrock, sixth chord, tercet, ternary, ternion, terzetto, three, threesome, tierce, tonic
triad, trefoil, trey, trialogue, triangle, tricorn, trident, triennium, trihedron, trilogy, trimester, trine, trinity, trinomial, trio, triphthong, triple, triple crown, triple threat, triplet, triplopy, tripod, triptych, trireme, triseme, triskelion, trisul, triumvirate, triune, triunity, trivet, troika, unbroken chord
ROGET THESAURUS
triad
Triality
N
triality, trinity, triunity, three,
triad, triplet, trey, trio, ternion, leash, shamrock, tierce, spike-team, trefoil, triangle, trident, triennium, trigon, trinomial, trionym, triplopia, tripod, trireme, triseme, triskele, triskelion, trisula, third power, cube, cube root, three, triform, trinal, trinomial, tertiary, ternary, triune, triarch, triadie, triple, tri-, tris-, tria juncta in uno.