Cm is C, Eb and G — with the third lowered a semitone.
It sounds darker than a major triad, and just as settled. The i of a minor key, and the vi, ii or iii of a major one.
Tonic — minor chords rest as readily as major ones.
Also written Cmin, C- or C minor.
Rock and pop often rock back and forth between Cm and F. The IV is major because the tune is dorian, a minor scale with a raised sixth; make it minor and the sound turns darker, plain minor.
Listen for: The fifth rises a whole step to the raised sixth and back. On the minor iv it rises only a half step.
Heard in“Love Is Blue”“Keep Searchin’” (coda)“Soul Kitchen”
Cm is the vi of E♭ major, a third below the I, and shares two of its notes. Keep falling in thirds, Eb, Cm, Ab, Fm, and above the bass only one note changes at each step, until Bb closes the phrase.
Listen for: The bass falls a third at a time. Above it one note changes per chord, each a step up: the key’s fifth to its sixth, third to fourth, tonic to second.
Heard in“Johnny Angel”
A minor-key song can cadence on Cm, a minor v, instead of the usual major V. With no leading tone the key sounds aeolian rather than minor.
Cm, a third above Ab, can stand in for it. The two share two notes, so the harmony stays the same and only its colour changes.
Heard in “Both Sides Now”
In which keys. Every note of Cm belongs to C minor, Eb major, F minor, G minor, Ab major and Bb major.
Every note of Cm is in C minor pentatonic, C blues, C natural minor, C dorian and C phrygian.
Each of those is a page: the scale across the neck, and the chords it harmonises into — which is where Cm sits in it. Every scale.
Change one note of Cm and you have (the minor third becomes the major third), (the fifth becomes the flat fifth), (the minor third becomes the second), (the minor third becomes the fourth), (add the sixth) or (add the flat seventh).
Cm is a minor chord — root, minor third, fifth. Minor chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.