A choir singer is someone who sings in a choir, which is a group of singers that perform together. An ALTO is a type of choir singer who has a lower vocal range than other singers in the choir. A CHORISTER is a singer who is part of a choir, and a TENOR is a type of choir singer who has a higher vocal range than other singers in the choir. Altos is the plural form of ALTO, and scales are musical exercises that choir singers use to practice their singing.