Sevenths A seventh chord a combination of a triad and a seventh interval above its root. The seventh is most commonly a minor seventh (10 halfsteps) or a major seventh (11 halfsteps) and the triad is generally major or minor. Below is a table of five different types of seventh chords and the scale degrees of the major scale they use. The half-diminished and diminished seventh chords are rarely used while the dominant seventh (written as X7) is used most frequently. Sevenths Dominant 7th (M triad + m7) I III V bVII Major 7th (M triad + M7) I III V VII Minor 7th (m triad + m7) I bIII V bVII Half-diminished 7th (d triad + m7) I bIII bV bVII Diminished 7th (d triad + d7) I bIII bV VI Play - Stop Back