Dyad (music)

In music, a dyad (less commonly, diad) is a set of two notes or pitches. The notes of a dyad can be played simultaneously or in succession. Notes played in succession form a melodic interval; notes played simultaneously form a harmonic interval.

Dyads can be classified by the interval between the notes. For example, the interval between C and E (four half steps) is a major third, which can imply a C major chord, made up of the notes C, E and G.