C eleventh chords
C11 chord for piano presented by keyboard diagrams.
Explanation: The C eleventh is a six note chord. Due to practical circumstances and/or dissonance the third (E) is omitted in C11 and/or the chord is played inverted. The chord is often abbreviated as C11.
Theory: The C eleventh chord is constructed by adding a third to a ninth chord.
Notes: C - E - G - Bb - D - F