Soprano: The highest of the vocal ranges for female singers. The operatic classification is the vocal range that can extend two octaves higher than middle C.
Mezzo Soprano: The middle female vocal range, typically extending from the A below middle C to two octaves above. Mezzo sopranos are thought to have a darker tone than sopranos, and are often cast in secondary parts to sopranos.
Contralto: The lowest operatic female vocal range. The contralto range lies between tenor and mezzo-soprano. Roles are not typically written specifically for contraltos, but rather for mezzo-sopranos who can dip down into the contralto range.
Tenor: The highest male vocal range within what is known as the modal register. The modal voice is what is typically used in speech. The range is between the C that is one octave below middle C and the A just above middle C.
Baritone: The most common male operatic vocal range, the baritone is between tenor and bass, and extends from the second G below middle C to the G above middle C.
Countertenor: The falsetto male vocal range roughly equivalent to the female mezzo-soprano or contralto.
Bass: The lowest vocal range.