Any kind of vocal performance without instrumental accompaniment.
Genre
Vermilion Sands 
A cappella
see also: 
All Music • britannica.com • everynoise.com • 
Freebase • 
Rate Your Music • 
TV Tropes • 
WikiData • 
Wikipedia
All Music • britannica.com • everynoise.com • Freebase • Rate Your Music • TV Tropes • WikiData • Wikipedia 
