Fig. 1 · C#dim on the keyboard

piano chord

C♯dim

C♯1E♭3G♭5

Two minor thirds stacked. The fifth is diminished, so it cannot be dropped without losing the chord.

Written the other way round it is D♭dim — the same twelve keys on a piano, a different piece of notation.

on guitar on ukulele the scale

What is true of it

C♯dim is C♯, E and G — 1, b3 and b5 counted from C♯.

C♯ in other shapes

C♯major C♯mminor C♯augaugmented C♯5power chord C♯sus2suspended second C♯sus4suspended fourth

Cdim Ddim D♯dim E♭dim Edim Fdim F♯dim G♭dim all 374