Chord & FretA#dim — diminished
Also written Bbdim — the same chord, spelled the other way.
Notes in A#dim: A# – C# – EFormula: 1 – b3 – b5In the formula, the numbers count steps of the major scale starting from the note that names the chord; "b" lowers a half step, "#" raises one — and a slash names the bass note.
The diminished triad pairs the minor third with the diminished fifth — that is, the fifth shrunk by a semitone. No note is left to rest on: the chord is unstable on purpose and asks for a continuation.
The same chord on all four instruments
Where to use it: A passing chord between two neighbours, and the seventh degree of major keys. It is almost never the arrival point — it exists to push the music to the next chord.
This is just one shape of A#dim. In Chord & Fret, you check it note by note, playing any shape as an arpeggio; open every variation on the neck, grouped by bass note; and set a capo — the diagrams redraw above it. Start free. Unlock everything with Pro. Plays offline.
See the whole neck in Chord & Fret →Part of the Triads family.