The Cm7 chord, or C minor 7, is a four-note chord that consists of the root note C, the minor third Eb, the perfect fifth G, and the minor seventh Bb. It is commonly used in various music genres, including jazz, blues, and pop, to create a rich, emotional sound. To play a Cm7 chord on the piano, you can use the notes C, Eb, G, and Bb together. On the guitar, it can be played using specific finger placements on the fretboard. This chord adds depth and complexity to musical compositions, making it a favorite among musicians.