The quality of a person's voice when singing.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "singing voice" in a sentence
"It was said that the Old Owl was Nanny Besom, (a witch, my dear!) who took the shape of a bird, but couldn't change her voice, and that that's why the owl sits silent all day for fear she should betray herself by speaking, and has no singing voice like other birds."
"Libbie is a great beauty, very bright and has the singing voice of an angel."