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