The D-flat dominant seventh flat five chord (abbreviated "Db7(b5) chord") is a four-note chord consisting of the notes D♭, F, A♭♭, and C♭. The chord is formed by lowering the fifth of a D-flat dominant seventh chord a half step.
D-flat dominant seventh flat five chord
D♭ F A♭♭ C♭
1 3 ♭5 ♭7
tetrad (four-note chord)