A11 chord

The A dominant eleventh chord (abbreviated A11 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 dominant ninth chord.

In practice, the third (C♯) and fifth (E) are often omitted from the A11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.