Meaning of TRIAD in English

noun a chord of three notes.

2. triad ·noun an element or radical whose valence is three.

3. triad ·noun the common chord, consisting of a tone with its third and fifth, with or without the octave.

4. triad ·noun a union of three; three objects treated as one; a ternary; a trinity; as, a triad of deities.

Webster English vocab.      Английский словарь Webster.