Ab11 chord

The A-flat dominant eleventh chord (abbreviated Ab11 chord) is a six-note chord consisting of the notes A♭, C, E♭, G♭, B♭, and D♭. The chord is formed by adding an eleventh to the A-flat dominant ninth chord.

In practice, the third (C) and fifth (E♭) are often omitted from the Ab11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.