Meaning of TRIAD in English

[] n [L triad-, trias, fr. Gk, fr. treis three] (1546) 1: a union or group of three: trinity

2: a chord of three tones consisting of a root with its third and fifth and constituting the harmonic basis of tonal music -- adj -- adv

Merriam-Webster English vocab.      Английский словарь Merriam Webster.