Vocal music
Vocal music is a type of singing performed by one or more singers, either with instrumental accompaniment, or without instrumental accompaniment (a cappella), in which singing provides the main focus of the piece. Music which employs singing but does not feature it prominently is generally considered to be instrumental music (e.g. the wordless women's choir in the final movement of Holst's symphonic work "The Planets") as is music without singing. Music without any non-vocal instrumental accompaniment is referred to as "a cappella".