An inversion occurs when a chord’s notes are rearranged, specifically which note in the bass of the chord. An A major chord in root position is A (root) C# (3rd) E (5th) 1st inversion is C# (3rd) E (5th) A (root) 2nd inversion is E (5th) A (root) C# (3rd) In Ex. 1 you can see these inversions played on the top three strings.