Bb 11th chord
Bb11 chord for piano presented by keyboard diagrams.
Explanation: The B flat eleventh is a six-note chord. To avoid dissonance the third (D) is normally omitted. The chord is also often played inverted. The chord is abbreviated as Bb11.
Theory: The Bb eleventh chord is constructed by adding a third to a ninth chord.
Notes: Bb - D - F - Ab - C - Eb