The terms 'Diminished' and 'Augmented' often frighten guitarists.

I think this is because like everything else to do with chord formulas, they are ideas that are easier to understand on the keyboard rather than on the fretboard.

A good way to think of the term 'diminished' is as 'even more minor than minor' and augmented: 'even more major than major'

Example: Major chords use the 1st, 3rd and 5th notes of the major scale (1,3,5). To augment the chord you 'stretch it' by sharping the 5th (1,3,#5)

Similarly: Minor chords use the 1st, flatted 3rd and 5th notes of the major scale (1,b3,5). To diminish the chord you 'shrink it' by flatting the 5th (1,3,b5).

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