A♯ (musical note)

A (A-sharp; French: la dièse) is the eleventh semitone of the solfège.

This note lies a chromatic semitone above A and a diatonic semitone below B, thus being enharmonic to B (French: si bémol).

When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the A above middle C is approximately 466.164Hz. See pitch (music) for a discussion of historical variations in frequency.