Abm7b5 chord for piano with keyboard diagram.
Explanation: The A flat minor seventh flat five is also called A flat half-diminished (also written as Abø). The chord is abbreviated Abm7b5, Abm7(b5) or Abm7-5.
Theory: The Abm7b5 is an A flat minor seventh with a lowered fifth.
Notes: Ab - B - D - Gb