Dominant (music)

This chord is said to have dominant function, which means that it creates an instability that requires the tonic for resolution.

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.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.In music theory, the dominant triad is a major chord, symbolized by the Roman numeral "V" in the major scale.

However, in a minor key, the seventh scale degree is often raised by a half step (♭ to ♮), creating a major chord.

The vast majority of harmonies designated as "essential" in the basic frame of structure must be I and V–the latter, when tonal music is viewed in broadest terms, an auxiliary support and embellishment of the former, for which it is the principal medium of tonicization.

The key immediately clockwise is the dominant key of the key immediately counterclockwise, and features either one more sharp or one less flat.
"Essentially, there are two harmonic directions: toward I and toward V. These primary diatonic triads form the harmonic axis of tonal music." [ 10 ]