A#11 chord

The A-sharp dominant eleventh chord (abbreviated A#11 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-sharp dominant ninth chord.

In practice, the third (C) and fifth (E♯) are often omitted from the A#11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.