C major 13th chord
Cmaj13 chord for piano with keyboard diagram.
Explanation: The C major thirteenth is a six-note chord (the 11th, F in the case of Cmaj13, is normally excluded). For practical reasons the chord is normally played with omitted notes and/or inverted. It is often abbreviated as Cmaj13 (not to be confused with C13).
Theory: The C major thirteenth chord is constructed by extending the major eleventh chord with a major thirteenth note.
Notes: C - E - G - B - D - A