A three-minute pop song is a cliché that describes the archetype of popular music, based on the average running-length of a typical single. The root of the "three-minute" length is likely derived from the original format of 78 rpm-speed phonograph records: at about 3 to 5 minutes per side, it is just long enough for the recording of a complete song.[1]
The rules of the Eurovision Song Contest do not permit entries to be longer than three minutes.