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.
Vocal music typically features sung words called lyrics, although there are notable examples of vocal music that are performed using non-linguistic syllables, sounds, or noises, sometimes as musical onomatopoeia, such as jazz scat singing. A short piece of vocal music with lyrics is broadly termed a song, although in different styles of music, it may be called an aria or hymn.