Dance music is 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...

 composed specifically to facilitate or accompany dancing

Dance

Dance is an art form that generally refers to movement of the body, usually rhythmic and to music, used as a form of expression, social interaction or presented in a spiritual or performance setting....

. It can be either a whole musical piece or part of a larger musical arrangement. In terms of performance, the major categories are live dance music and recorded dance music.
Folk dance music is music accompanying traditional dance

Folk dance

The term folk dance describes dances that share some or all of the following attributes:*They are dances performed at social functions by people with little or no professional training, often to traditional music or music based on traditional music....

 and may be contrasted with historical/classical, and popular/commercial dance music. An example of folk dance music in the United States is the old-time music

Old-time music

Old-time music is a genre of North American folk music, with roots in the folk music of many countries, including England, Scotland, Ireland and countries in Africa. It developed along with various North American folk dances, such as square dance, buck dance, and clogging. The genre also...

 played at square dance

Square dance

Square dance is a folk dance with four couples arranged in a square, with one couple on each side, beginning with Couple 1 facing away from the music and going counter-clockwise until getting to Couple 4. Couples 1 and 3 are known as the head couples, while Couples 2 and 4 are the side couples...

s and contra dance

Contra dance

Contra dance refers to several partnered folk dance styles in which couples dance in two facing lines...

s.