The "Disco Break" is a term used to describe the point in a song where the music is at it's prime and DJ's sratch to keep the music going. Disco DJ's used scratching during the 70's to keep the music fresh. Because the disco break was the best part of the song, B-Boys would use this time to dance, thus the term "Break-Dancing" was coined.
Man, when the disco broke things got hectic at the 313.