Triad (music)

In music, a triad is a set of three notes (or "pitch classes") that can be stacked vertically in thirds.

The triad's members, from lowest-pitched tone to highest, are called:[1] Some 20th-century theorists, notably Howard Hanson,[2] Carlton Gamer,[3] and Joseph Schillinger[4] expand the term to refer to any combination of three different pitches, regardless of the intervals.

The root of a triad, together with the degree of the scale to which it corresponds, primarily determine its function.

Secondarily, a triad's function is determined by its quality: major, minor, diminished or augmented.

"[8] The other triads in diatonic keys include the supertonic, mediant, submediant, and leading-tone, whose roots are the second, third, sixth, and seventh degrees (respectively) of the diatonic scale, symbolized ii, iii, vi, and viio.