A Dim Chord

How the A Dim chord is built: its notes, its interval structure, and where it fits.

The A Dim chord contains 3 notes: A – C – D#. It belongs to the diminished & augmented family of chord qualities. Like every chord, it is defined by the distances (intervals) between its notes, not by any one instrument — which is why the same formula names the chord whether it is voiced on a fretboard, a keyboard, or a choir.