The A-sharp half-diminished seventh chord (abbreviated "A#m7(b5) chord") is a four-note chord consisting of the notes A♯, C♯, E, and G♯. The chord is formed by lowering the fifth of a A-sharp minor seventh chord a half step.
A-sharp half-diminished seventh chord
A-sharp half-diminished chord A-sharp minor seventh flat five chord
A♯ C♯ E G♯
1 ♭3 ♭5 ♭7
A♯ø A♯ø7 A♯m7b5 A♯–7(b5) A♯mi7(b5) A♯min7(b5)
tetrad (four-note chord)