G♯ (G-sharp) or Sol Dièse is the ninth semitone of the solfege. In the German pitch nomenclature, it is known as gis. It lies a chromatic semitone above G and a diatonic semitone below A, thus being enharmonic to La Bémol or A♭ (A flat). When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the G♯ semitone is approximately 415.305 Hz. See pitch (music) for a discussion of historical variations in frequency.