Leading-tone triad in the context of "Dominant (music)"

In music, the dominant is the fifth scale degree () of the diatonic scale. It is called the dominant because it is second in importance to the first scale degree, the tonic. In the movable do solfège system, the dominant note is sung as "So(l)".

The triad built on the dominant note is called the dominant chord. The chord is said to have dominant function, which means that it creates an instability that requires the tonic for resolution. Dominant triads, seventh chords, and ninth chords typically have dominant function. Leading-tone triads and leading-tone seventh chords may also have dominant function.