A singer or vocalist is a type of musician who sings, i.e. uses the voice as an instrument to make music.

In classical music and in opera, voices are treated just like musical instruments, thus special careers were developed out of each principal pitch.

Voices are commonly classified into: Female voices:

• soprano
• mezzo-soprano
• alto

Male voices:

• countertenor
• tenor
• baritone
• bass
• castrato