A♭ (musical note)
A (A-flat; also called la bémol) is the ninth semitone of the solfège.

It lies a diatonic semitone above G and a chromatic semitone below A, thus being enharmonic to G, even though in some musical tunings, A will have a different sounding pitch than G.

When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the A above middle C (or A4) is approximately 415.305 Hz. See pitch (music) for a discussion of historical variations in frequency.

A/G is the only note to have only one other enharmonic.

Designation by octave

Scales

Common scales beginning on A
A Major: A B C D E F G A
A Natural Minor: A B C D E F G A
A Harmonic Minor: A B C D E F G A
A Melodic Minor Ascending: A B C D E F G A
A Melodic Minor Descending: A G F E D C B A

Diatonic scales
A Ionian: A B C D E F G A
A Dorian: A B C D E F G A
A Phrygian: A B C D E F G A
A Lydian: A B C D E F G A
A Mixolydian: A B C D E F G A
A Aeolian: A B C D E F G A
A Locrian: A B C D E F G A

Jazz melodic minor
A Ascending Melodic Minor: A B C D E F G A
A Dorian ♭2: A B C D E F G A
A Lydian Augmented: A B C D E F G A
A Lydian Dominant: A B C D E F G A
A Mixolydian ♭6: A B C D E F G A
A Locrian ♮2: A B C D E F G A
A Altered: A B C D E F G A