C#maj11 chord

The C-sharp major eleventh chord (abbreviated "C#maj11 chord") is a six-note chord consisting of the notes C♯, E♯, G♯, B♯, D♯, and F♯. The chord is formed by adding an eleventh to a C-sharp major ninth chord.

In practice, the fifth (G♯) is often omitted from the C#maj11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.