dominantakord

A dominant chord is a fundamental chord type in Western music theory, characterized by its specific interval structure and role within harmonic progressions. Typically composed of three notes—a root, a major third, and a minor seventh—it is often notated as a major triad with a minor seventh added above the root, such as V7 in a key, where "V" represents the fifth scale degree. For example, in the key of C major, the dominant chord would be G7, consisting of the notes G, B, D, and F.

The dominant chord derives its name from its position in the diatonic scale, serving as the fifth degree (V) of the scale. Its defining feature is the minor seventh interval between the root and the seventh note, creating a strong sense of tension that seeks resolution to the tonic (I) chord. This tension is a key element in classical and popular music, driving harmonic movement and contributing to the cadential structure of phrases.

In practice, the dominant chord often functions as a pivot point in a musical piece, particularly in progressions like the V-I (plagal) or V-vi-IV-I (common in pop and jazz) cadences. Variations of the dominant chord, such as the dominant seventh flat five (V7♭5) or dominant ninth (V9), expand its harmonic possibilities by adding additional notes, which can introduce chromaticism or modal inflections. These extensions are common in jazz, blues, and other genres that emphasize rich harmonic textures.

The dominant chord’s role extends beyond tonal music, appearing in modal scales and non-Western traditions where similar interval structures create analogous harmonic tensions. Its versatility and functional role make it one of the most studied and widely used chord types in music theory.