Dyads

In music, a dyad is a set of two notes or pitches.Although most chords have three or more notes, in certain contexts a dyad may be considered to be a chord. The most common two-note chord is made from the interval of a perfect fifth, which may be suggestive of music of the Medieval or Renaissance periods, or various kinds of rock music. When fifths are missing from major or minor tertian triads, on the other hand, they are generally still considered triads, rather than dyads.

Since an interval is the distance between two pitches, dyads may be classified by the interval each entails. When the pitches of a dyad occur in succession, they may be regarded as forming a melodic interval. When they occur simultaneously, they may be regarded as forming a harmonic interval.