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. This 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.

In very much conventionally tonal music, harmonic analysis will reveal a broad prevalence of the primary (often triadic) harmonies: tonic, dominant, and subdominant (i.e., I and its chief auxiliaries a 5th removed), and especially the first two of these.

— Wallace Berry (1976)

The scheme I-x-V-I symbolizes, though naturally in a very summarizing way, the harmonic course of any composition of the Classical period. This x, usually appearing as a progression of chords, as a whole series, constitutes, as it were, the actual "music" within the scheme, which through the annexed formula V-I, is made into a unit, a group, or even a whole piece.

— Rudolph Reti, (1962)

In music theory, the dominant triad is a major chord, symbolized by the Roman numeral "V" in the major scale. In the natural minor scale, the triad is a minor chord, denoted by "v". However, in a minor key, the seventh scale degree is often raised by a half step (♭ to ♮), creating a major chord.

These chords may also appear as seventh chords: typically as a dominant seventh chord, but occasionally in minor as a minor seventh chord v⁷ with passing function: