ALTO definition

(1) (of a musical instrument) second highest member of a group

"Alto clarinet or recorder"

(2) Of or being the highest male voice; having a range above that of tenor

(3) Of or being the lowest female voice

(4) The pitch range of the lowest female voice

(5) (of a musical instrument) the second highest instrument in a family of musical instruments

(6) The highest adult male singing voice

(7) The lowest female singing voice

(8) A singer whose voice lies in the alto clef