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