So in a C chord, the root note of the chord is a C. The I is the root note, and a major chord is made up of the I, III, and V notes, whereas a minor chord is made up of the I, IV, and V notes. The uppercase stand for major chords, while lowercase is minor. You can see there’s a mix of uppercase and lowercase letters. It helps figure out the scale degree on which a chord is based.
This is also known as the Nashville Numbering System. These seven notes are assigned Roman numerals in this format: I – ii – iii – IV – V – vi – vii. For instance, in C major scale, the notes are C, D, E, F, G, A, B, and C. It is a particular sequence of chords, usually in the same scale or key, played to give the song a meaningful direction.
In its simplest form, a chord progression is the foundation of a song.
