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Theory · glossary

Triad

Also called three-note chord, major triad, minor triad

A triad is a three-note chord built by stacking two thirds: a root, the note a third above it and the note a fifth above the root. C major (C E G) and A minor (A C E) are triads, and so are most chords beginners learn first.

Most chords in pop and folk songs are triads: three notes stacked in thirds. Start on a root, skip a note of the scale, take the next, skip one, take the next. In C major that gives C E G. The size of the two thirds decides the type. A major third spans 4 semitones and a minor third spans 3.

TypeNotesThirds, low to highSound
Major (C)C E Gmajor, minorbright, settled
Minor (Cm)C Eb Gminor, majordarker, often sad
Diminished (Cdim)C Eb Gbminor, minortense, wants to move
Augmented (Caug)C E G#major, majorfloating, unresolved

Build a triad on each note of C major and you get the key’s seven chords: C, Dm, Em, F, G, Am and Bdim (B D F). Six of them are major or minor. The augmented triad never appears in a major key; it turns up in A harmonic minor as C E G#.

The notes can come in any order or octave and it is still the same triad. E G C and G C E are C major in inversion, written C/E and C/G. The open C chord on guitar sounds five strings, C E G C E, and it is still a triad because only three different notes ring.

A chord symbol with no number, like C, Am or F#m, means a triad. Add a fourth note a seventh above the root and you get a seventh chord. How to read chord symbols covers the letters that change a triad, and the chords in C major page lists all seven with their notes.

In Gelato Synth’s Chords mode, the chord-type row has a Triad setting, and it switches every pad to a plain three-note chord at once.

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