Bb7(b9) chord
The B-flat dominant minor ninth chord (abbreviated "Bb7(b9) chord") is a five-note chord consisting of the notes B♭, D, F, A♭, and C♭. The chord is formed by adding a major ninth to a B-flat dominant seventh chord.
In practice, the fifth (F) is often omitted from the Bb7(b9) chord because it's not always possible to play all notes simultaneously.
Name
B-flat dominant minor ninth chord
Notes
B♭ D F A♭ C♭
Intervals
1 3 5 ♭7 ♭9
Chord symbol
B♭7(b9)
Alternative symbol
B♭7b9
Type
pentad (five-note chord)