The dim7 chord is based on the 1st (Root) - b3rd - b5th & bb7th notes of a major scale. Inversions change the order of the notes by playing a different note as the lowest note of the chord. The chord symbols are written using a slash (/) such as Cdim7/Eb which means to play a Cdim7 chord with the Eb note as the lowest note in the chord. These chord symbols are common to other instruments such as keyboards.
