C#9 chord
The C-sharp dominant ninth chord (abbreviated "C#9 chord") is a five-note chord consisting of the notes C♯, E♯, G♯, B, and D♯. The chord is formed by adding a major ninth to a C-sharp dominant seventh chord.
In practice, the fifth (G♯) is sometimes omitted from the C#9 chord because it's not always possible to play all notes simultaneously.
Name
C-sharp dominant ninth chord
Notes
C♯ E♯ G♯ B D♯
Intervals
1 3 5 ♭7 9
Chord symbol
C♯9
Type
pentad (five-note chord)