Cm7

Cm7, short for C minor seventh, is a four-note chord formed by the root C, a minor third Eb, a perfect fifth G, and a minor seventh Bb. In letter names: C Eb G Bb. The chord is built with a 1-b3-5-b7 structure.

Used in many genres, Cm7 functions as a tonic minor seventh in C natural minor, and as the ii chord in Bb major (ii–V–I progression: Cm7–F7–Bb). It is common in jazz, pop, and film music as a versatile color chord and as a diatonic color in related keys.

Voicings and inversions: root position: C Eb G Bb; first inversion: Eb G Bb C; second inversion: G Bb C Eb; third inversion: Bb C Eb G. In jazz notation it is Cm7; sometimes written Cmin7.

Extensions: Further color can be added as Cm9 (C Eb G Bb D), Cm11, Cm13, etc., but basic form is the triad plus a minor seventh.

Notes: Cm7 is the standard representation of a C minor seventh chord; it should not be confused with Cm(maj7), which would include a major seventh (B natural) instead of Bb. The chord is closely related to its diatonic function in minor keys and in ii–V–I progressions in major keys such as Bb.