Bm7b5 chord for piano with keyboard diagram.
Explanation: The B minor seventh flat five is also called B half-diminished (also written as Bø). The chord is abbreviated Bm7b5, Bm7(b5) or Bm7-b5.
Theory: The Bm7b5 is a B minor seventh with a lowered fifth.
Notes: B - D - F - A