alto (Adjective) — Of or being the lowest female voice.
alto (Adjective) — Of or being the highest male voice; having a range above that of tenor.
alto (Adjective) — (of a musical instrument) second highest member of a group. ex. "alto clarinet or recorder"
alto (Noun) — A singer whose voice lies in the alto clef.
alto (Noun) — The lowest female singing voice.
alto (Noun) — The highest adult male singing voice.
alto (Noun) — (of a musical instrument) the second highest instrument in a family of musical instruments.
alto (Noun) — The pitch range of the lowest female voice.