A 9 chord, or ninth chord, is an extended chord that builds upon a seventh chord by adding an extra note on top that is nine steps away from the root. It is often used in jazz, blues, and some pop music to add complexity and a jazzy feel to chord progressions. In a major 9 chord, the extensions consist of a major third, perfect fifth, and a major seventh, with the ninth note creating a sense of brightness. Meanwhile, in a dominant 9 chord, the seventh note is flattened, resulting in a more tension-filled sound that resolves well to a tonic chord. Popular fingerings on the guitar often use barre chords to create a rich, full sound.