Seventh chord
A seventh chord is a four-note chord: a triad with a further third on top. It is named after the seventh between the lowest and the highest tone. The most important is the dominant seventh chord, which pulls strongly to the tonic.
Four tones instead of three
If you stack a further third on the triad, a seventh chord arises. The triad is the basic building block, but harmony only becomes really rich through extensions. Every additional tone brings a new nuance of tension between the poles of rest and urge. Seventh chords and further extensions are the reason why jazz and modern harmony sound more colourful than a purely triadic setting.
| Seventh chord | Structure | Example | Sound |
|---|---|---|---|
| Dominant seventh | major triad + minor seventh | G7 | full of tension, pulls to the tonic |
| Major seventh (maj7) | major triad + major seventh | Cmaj7 | soft, jazzy, floating |
| Minor seventh (m7) | minor triad + minor seventh | Dm7 | round and mild |
| Half-diminished (m7♭5) | diminished triad + minor seventh | Bm7♭5 | typical in minor cadences |
The dominant seventh chord
It sits on the dominant and contains a strong dissonance: the tritone between the major third and the minor seventh. You hear that it sounds “unfinished” and wants to go on. This built-in pull makes it the engine of countless closing formulas, from Bach to today's pop song. In blues and jazz the minor seventh is the characteristic interval. The diminished seventh chord is a special case: it consists of three minor thirds and has no clear root, see Diminished seventh chord.
In a chord progression seventh chords are written with an addition: C7 for the dominant form, Cmaj7 or CΔ for the major seventh, Dm7 for the minor seventh chord.
Common mistakes
- Mixing up seventh chord and seventh: The seventh is the interval, the seventh chord the whole four-note chord.
- Swapping major and minor seventh: G7 has the minor seventh (F), Cmaj7 the major one (B).
- Confusing half-diminished and diminished: The half-diminished chord has a minor seventh and a clear root.
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Related terms
Dominant seventh chordDiminished seventh chordTriadChordSeventh (interval)Minor seventhMajor seventhDominantChord inversion
Editor: Maik Krohm · reviewed on 3 October 2026
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