Dyad (music)
In music, a dyad (less commonly, diad) is a set of two notes or pitches that, in particular contexts, may imply a chord.
Dyads can be classified by the interval between the notes. For example, the interval between C and E is a major third, which can imply a C major chord, made up of the notes C, E and G. When the pitches of a dyad occur in succession, they form a melodic interval. When they occur simultaneously, they form a harmonic interval.