A♭, or A flat, is a musical note that is one semitone lower than A. It is represented by the symbol "A♭" and is commonly used in various musical scales and compositions. In the context of the piano, A♭ is the black key immediately to the left of the A key. In Western music, A♭ is often found in the A♭ major scale, which consists of the notes A♭, B♭, C, D♭, E♭, F, and G. This note is also used in the A♭ minor scale, which includes A♭, B♭, C♭, D♭, E♭, F♭, and G♭. A♭ plays a significant role in various genres, including classical, jazz, and pop music.