C major ninth chord
Cmaj9 chord for piano with keyboard diagram.
Explanation: The C major ninth is a five note chord and can be regarded as a Cmaj7 with an added ninth. It is often abbreviated as Cmaj9 (should not be confused with C9).
Theory: The Cmaj9 chord is constructed with a root, a major third, a perfect fifth, a major seventh and a major ninth.
Notes: C - E - G - B - D