Triad (music)

In music, a triad is a set of three notes (or "pitch classes") that can be stacked vertically in thirds. Triads are the most common chords in Western music. When stacked in thirds, notes produce triads. The triad's members, from lowest-pitched tone to highest, are called: the root Note: Inversion does not change the root. (The third or fifth can be the lowest note.) the third – its interval above the root being a minor third (three semitones) or a major third (four semitones) the fifth – its interval above the third being a minor third or a major third, hence its interval above the root being a diminished fifth (six semitones), perfect fifth (seven semitones), or augmented fifth (eight semitones). Perfect fifths are the most commonly used interval above the root in Western classical, popular and traditional music. Some 20th-century theorists, notably Howard Hanson, Carlton Gamer, and Joseph Schillinger expand the term to refer to any combination of three different pitches, regardless of the intervals. Schillinger defined triads as "A structure in harmony of but three parts; conventionally, but not necessarily, the familiar triad of ordinary diatonic harmony." The word used by other theorists for this more general concept is "trichord". Others use the term to refer to combinations apparently stacked by other intervals, as in "quartal triad"; a combination stacked in thirds is then called a "tertian triad". 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. Major and minor triads are the most commonly used triad qualities in Western classical, popular and traditional music. In standard tonal music, only major and minor triads can be used as a tonic in a song...