A Suspended 2nd (Asus2)
1+2+5
Notes in A Suspended 2nd
A (root)BE
Inversions
Same notes as A Suspended 2nd, with a different chord tone as the lowest note. Useful for smoother movement between chords instead of jumping around the keyboard.
Root position
A in the bass
1st inversion
B in the bass (Asus2/B)
2nd inversion
E in the bass (Asus2/E)
The notes A, B and E make up A Suspended 2nd.
Suspended chords pull the third out entirely, so they land somewhere between major and minor rather than picking a side. Sus2 fills the gap with a major second sitting close to the root, which gives it an open, slightly hollow color. It's a favorite way to add movement to a strummed or arpeggiated part without changing the underlying harmony.