Vocal music is a genre of music

Music

Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...

 performed by one or more singers, with or without instrumental accompaniment, in which singing

Singing

Singing is the act of producing musical sounds with the voice, and augments regular speech by the use of both tonality and rhythm. One who sings is called a singer or vocalist. Singers perform music known as songs that can be sung either with or without accompaniment by musical instruments...

 (i.e. vocal performance) provides the main focus of the piece. Music which employs singing but does not feature it prominently is generally considered instrumental music (e.g. the wordless women's choir in the final movement of Holst

Gustav Holst

Gustav Theodore Holst was an English composer. He is most famous for his orchestral suite The Planets....

's The Planets

The Planets

The Planets, Op. 32, is a seven-movement orchestral suite by the English composer Gustav Holst, written between 1914 and 1916. Each movement of the suite is named after a planet of the Solar System and its corresponding astrological character as defined by Holst...

) as is music without singing.