In music theory, a diminished triad (or minor flatted fifth) is a triad consisting of minor third and lowered fifth or in degrees: 1 ♭3 ♭5
Usually you can see the diminished C chord in the following forms: C°, Cdim, Cm♭5, Cm-5, Cmb5, Cm-5 or Cm♭5. Knowing that you can find other diminished chords in the dictionary by looking for chords which are minor and have -5 using Chord Dictionary screen or using Reverse Chord Lookup screen.
Take look at the following screen showing you how to find Cm7-5, C°7 or CØ chord using Reverse Chord Lookup:
