A mezzo-soprano or mezzo (; ; meaning "half soprano") is a type of classical female singing voice whose vocal range lies between the soprano and the contralto voice types. The mezzo-soprano's vocal range usually extends from the A below middle C to the A two octaves above (i.e. A3–A5 in scientific pitch notation, where middle C = C4; 220–880 Hz). In the lower and upper extremes, some mezzo-sopranos may extend down to the F below middle C (F3, 175 Hz) and as high as "high C" (C6, 1047 Hz).