The A added ninth chord (abbreviated "Aadd9 chord") is a four-note chord consisting of the notes A, C, E, and B. The chord is formed by adding a major ninth to a A major chord.

Often, a major second is played instead of the major ninth since they are the same note.

Name
A added ninth chord
Synonym
A added second chord
Notes
A C E B
Intervals
1 3 5 9
Chord symbol
Aadd9
Alternative symbols
A(add9) Aadd2 A(add2)
Type
Tetrad (four-note chord)

Aadd9 chord on piano

Aadd9 chord on guitar

Aadd9 chord on ukulele

Aadd9 chord on the staff