F dim7
The F dim7 chord consists of the F (Perfect unison), G# (Minor third), B (Diminished fifth) and D (Major sixth) notes.

How to play the F dim7 chord
- Find F (Root) on the piano keyboard
- Add G# (Minor third) — 3 semitones above F
- Add B (Diminished fifth) — 6 semitones above F
- Add D (Major sixth) — 9 semitones above F
- Press all 4 notes simultaneously to sound the F dim7 chord