To expand on what Don Firth said--if you've listened to any classical music at all, you know that Baroque composers frequently composed Suites, and you know that they consisted of a number (four or more) of movements--Generally, each movement was a dance melody, which was often taken from the popular music of the day.

The standard sequence alternated slow and quick melodies---the names of the movements are familiar to everyone Allemande, then Courant, Sarabande, and Gigue. Between the last two parts, composers often inserted a few other dances, most of which were French , such as the bourree, gavotte, passacaglia, polonaise, saltarello, and occasionally a few airs(which are songs, not dances)--

Suites were not intended for dancing, and the dance "feel" was generally slowed down and evened out to allow the composer to explore harmonic ideas. Main thing is that the melodies that the composers worked with were pretty much folk music, so when someone uses one for a song, they really are just bring things around full circle--