alto

noun pl. altos

1. the range of the lowest female voice or the highest male voice; specif.,
   1. contralto
   2. countertenor
2. 1. a voice or singer with such a range
   2. an instrument with a similar range within its family, as an alto saxophone
   3. a part for such a voice or instrument
3. in four-part harmony, the second highest part

adjective