Progressive rock is a radio station programming format that prospered in the late 1960s and early 1970s, in which the disc jockeys are given wide latitude in what they may play, similar to the freeform format but with the proviso that some kind of rock music is almost always what is played. The name for the format came from around 1968, when serious disc jockeys were playing "progressive 'music for the head'" and discussing social issues in between records.