Overview

A seventh chord is a chord consisting of a triad (three notes stacked in thirds) with an additional note a seventh above the root, creating a four-note harmony. This extra interval adds tension, color, and a sense of movement, making seventh chords fundamental in Western music, particularly in jazz, classical, and popular genres. Common types include major seventh, minor seventh, dominant seventh, half‑diminished seventh, and fully diminished seventh, each defined by the quality of the triad and the seventh interval.

1 History and theory

1.1 Definition and notation

The seventh chord originates from the practice of adding a fourth note a seventh above the root to a triad, a development that emerged in the late Renaissance and became standard in Baroque continuo. In modern notation, a seventh chord is indicated by the root letter followed by a symbol denoting the chord quality and seventh type (e.g., Cmaj7, G7, Dø7). The chord is built in thirds: root, third, fifth, and seventh.

1.2 Intervals and chord quality

The quality of a seventh chord depends on the intervals between the root and the other notes. The triad may be major, minor, augmented, or diminished; the seventh may be major, minor, or diminished. The combination determines the chord’s name and characteristic sound. For example, a major triad with a major seventh yields a major seventh chord; a major triad with a minor seventh yields a dominant seventh.

2 Types of seventh chords

2.1 Major seventh

A major seventh chord consists of a major triad and a major seventh interval (e.g., C–E–G–B). It produces a warm, somewhat dreamy sound, often used in jazz ballads and impressionist music. Notation: Cmaj7 or CΔ7.

2.2 Minor seventh

A minor seventh chord comprises a minor triad and a minor seventh (e.g., C–E♭–G–B♭). Its sound is mellow and slightly melancholic, common in jazz, funk, and popular music. Notation: Cm7 or C–7.

2.3 Dominant seventh

A dominant seventh chord uses a major triad and a minor seventh (e.g., C–E–G–B♭). It carries strong tension that typically resolves to the tonic, making it a cornerstone of tonal harmony. Notation: C7.

2.4 Half‑diminished seventh (minor seventh flat five)

A half‑diminished seventh chord combines a diminished triad with a minor seventh (e.g., C–E♭–G♭–B♭). Its sound is tense and unstable, frequently appearing as the ii chord in minor keys. Notation: Cø7 or Cm7♭5.

2.5 Diminished seventh

A diminished seventh chord consists of a diminished triad and a diminished seventh (e.g., C–E♭–G♭–B♭♭). All intervals are minor thirds, creating a symmetrical, highly dissonant chord used for modulation and dramatic effect. Notation: C°7.

2.6 Other variants

2.6.1 Augmented seventh

An augmented seventh chord typically pairs an augmented triad with a minor seventh (e.g., C–E–G♯–B♭). It appears in jazz and blues as an altered dominant. Notation: C+7 or C7♯5.

2.6.1.1 Augmented major seventh

This variant uses an augmented triad with a major seventh (e.g., C–E–G♯–B). It is rarer, with a bright, unstable quality, found in modern classical and fusion music. Notation: C+maj7.

2.6.2 Minor‑major seventh

A minor‑major seventh chord combines a minor triad with a major seventh (e.g., C–E♭–G–B). Its sound is bittersweet and exotic, often used in film scores and jazz harmony. Notation: Cm(maj7).

3 Inversions and voicings

All seventh chords can be inverted by placing a chord tone other than the root in the bass. Inversions are numbered according to which note is lowest.

3.1 Root position

In root position, the root is the lowest note. The chord is spelled root–third–fifth–seventh (e.g., C–E–G–B for Cmaj7).

3.2 First inversion

The third is in the bass. The voicing from bottom to top is third–fifth–seventh–root (e.g., E–G–B–C). This inversion softens the root’s prominence.

3.3 Second inversion

The fifth is in the bass. The order is fifth–seventh–root–third (e.g., G–B–C–E). This inversion is common in passing chords.

3.4 Third inversion

The seventh is in the bass. The chord is voiced seventh–root–third–fifth (e.g., B–C–E–G). This inversion is often used as a suspension leading to a root‑position chord.

4 Harmonic function

4.1 In classical harmony

In common‑practice tonality, seventh chords primarily appear as dominant sevenths (V7) resolving to the tonic. The leading‑tone seventh (vii°7) and the supertonic seventh (ii7) also serve pre‑dominant functions. Classical composers treat seventh chords as dissonances requiring proper preparation and resolution.

4.2 In jazz harmony

Jazz harmony treats seventh chords as the basic unit of harmonic language. All chord types are used freely, often extended with ninths, elevenths, and thirteenths. The ii–V–I progression highlights the role of minor seventh and dominant seventh chords. Jazz musicians frequently alter tensions (e.g., ♭9, ♯11) for color.

5 Common progressions

5.1 ii–V–I

The ii–V–I is the most ubiquitous progression in jazz and common in popular music. In C major, ii7 is Dm7, V7 is G7, and I is Cmaj7. The minor seventh and dominant seventh chords create a smooth, cadential motion.

5.2 Blues progressions

Twelve‑bar blues relies heavily on dominant seventh chords built on the I, IV, and V degrees. For example, in C blues: C7–F7–C7–C7 / F7–F7–C7–C7 / G7–F7–C7–G7. The blues progression uses the dominant seventh’s tension and the “blue notes” from its flatted third and seventh.

6 Notable examples in music

6.1 Classical repertoire

  • Ludwig van Beethoven, Symphony No. 5 (1808): The famous opening uses a dominant seventh (G7) resolving to C minor.
  • Claude Debussy, “Clair de Lune” (1890): Features lush major seventh chords, illustrating impressionist harmony.
  • Wolfgang Amadeus Mozart, “Dissonance” Quartet (1785): The Adagio introduction includes a diminished seventh chord that defines its unsettling mood.

6.2 Jazz standards

  • George Gershwin, “Summertime” (1935): The opening uses a minor seventh (Dm7) and major seventh (Cmaj7) over a bluesy melody.
  • John Coltrane, “Giant Steps” (1960): The chord progression cycles through dominant seventh and major seventh chords over a rapid series of key changes.
  • Duke Ellington, “Satin Doll” (1953): The melody floats over a sequence of minor seventh and dominant seventh chords.
  • The Beatles, “Something” (1969): The introduction features a major seventh chord (Cmaj7) creating a warm, ascending effect.
  • Stevie Wonder, “Superstition” (1972): The funk rhythm is built on a dominant seventh‑based clavinet riff.
  • Radiohead, “The National Anthem” (2000): Uses a half‑diminished chord (Eø7) in the bass line to generate unease.