What is a Seventh Chord?

A seventh chord is a type of chord that includes four different notes built by stacking three intervals of a third on top of each other. In addition to the root, third, and fifth found in a basic triad, a seventh chord adds another note called the seventh. This extra note creates a richer and more complex sound than a simple three-note chord.

The seventh note is measured from the root of the chord and can appear in different forms depending on the type of seventh chord. For example, a C dominant seventh chord (C7) contains the notes C, E, G, and B♭. In this case, B♭ is the seventh interval above the root note C. This added note creates tension that often resolves to another chord in a progression.

Seventh chords are widely used in many musical styles, including jazz, blues, classical, pop, and rock. They are an important part of harmony because they add depth and movement to chord progressions. Musicians use different types of seventh chords—such as major seventh, minor seventh, and dominant seventh—to create different emotional colors and harmonic textures in music.