The A-flat dominant ninth chord (abbreviated "Ab9 chord") is a five-note chord consisting of the notes A, C, E, G, and B. The chord is formed by adding a major ninth to a A-flat dominant seventh chord.

In practice, the fifth (E) is sometimes omitted from the Ab9 chord because it's not always possible to play all notes simultaneously.

Name
A-flat dominant ninth chord
Notes
A C E G B
Intervals
1 3 5 7 9
Chord symbol
A9
Type
pentad (five-note chord)

Ab9 chord on piano

Ab9 chord on guitar

Ab9 chord on ukulele

Ab9 chord on the staff