Akademik

ternary
adj.
1 composed of three parts.
2 Math. using three as a base (ternary scale).
Phrases and idioms:
ternary form Mus. the form of a movement in which the first subject is repeated after an interposed second subject in a related key.
Etymology: ME f. L ternarius f. terni three each

Useful english dictionary. 2012.