Lesson 1 of Writing music built the triad: a root, a third and a fifth. This lesson adds the fourth note most chords in pop, soul and jazz carry, the seventh, and shows what happens when the root is not the lowest note.
Seventh chords
Add a seventh above a triad and you get a seventh chord. Textbooks name them by the type of triad and the type of seventh.
| Chord | Triad + seventh | Notes | Semitones up from the root |
|---|---|---|---|
| Major seventh (Cmaj7) | Major triad + major seventh | C E G B | 4 · 7 · 11 |
| Dominant seventh (C7) | Major triad + minor seventh | C E G B♭ | 4 · 7 · 10 |
| Minor seventh (Cm7) | Minor triad + minor seventh | C E♭ G B♭ | 3 · 7 · 10 |
| Half-diminished (Cm7♭5) | Diminished triad + minor seventh | C E♭ G♭ B♭ | 3 · 6 · 10 |
When someone says just "a seventh chord", they usually mean the dominant seventh: a major triad with a minor seventh on top. If a chord symbol names no type at all, as in C7, the triad is taken as major and the seventh as minor.
Inversions
A C major triad holds C, E and G. Which of the three is lowest decides its inversion.
| Position | Lowest note | Order from the bottom |
|---|---|---|
| Root position | The root, C | C E G |
| First inversion | The third, E | E G C |
| Second inversion | The fifth, G | G C E |
A chord is in root position whenever its root is the lowest note, however the notes above are spread or doubled. Inversions keep the chord's name and change its weight: an inverted chord often sits more lightly and lets the bass line move by step, which is the subject of lesson 10.
Sources
Every date, name, tempo and origin on this page comes from these pages, read on 2026-10-24.