The G half-diminished seventh chord (abbreviated "Gm7(b5) chord") is a four-note chord consisting of the notes G, B♭, D♭, and F. The chord is formed by lowering the fifth of a G minor seventh chord a half step.
G half-diminished seventh chord
G half-diminished chord G minor seventh flat five chord
G B♭ D♭ F
1 ♭3 ♭5 ♭7
Gø Gø7 Gm7b5 G–7(b5) Gmi7(b5) Gmin7(b5)
Tetrad (four-note chord)