Cb9 chord

The C-flat dominant ninth chord (abbreviated Cb9 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 the C-flat dominant seventh chord.

In practice, the fifth (G♭) is sometimes omitted from the Cb9 chord because it's not always possible to play all notes simultaneously.