Gm7b5 chord for piano with keyboard diagram.
Explanation: The G minor seventh flat five is also called G half-diminished (also written as Gø). The chord is abbreviated Gm7b5, Gm7(b5) or Gm7-b5.
Theory: The Gm7b5 is a G minor seventh with a lowered fifth.
Notes: G - Bb - Db - F