Originally as a technique in hip-hop music: an act of spinning a record back by hand, without lifting the stylus, in order to play a (section of) a record again.
This technique is often used to play a short section of music repeatedly, typically by alternating between two turntables playing copies of the same record. It is also the technique typically used in performing rewinds, and the two terms are sometimes used synonymously.
1980s. From spin + back.