Not many of us listen to the radio these days; most of us are glued to the TV. This is what happened in the United States as well in the 1940s; the radio took a back seat to television. With the exception of news, all other popular radio programmes made a beeline for the idiot box. In order to win back some of its old audience, radio stations began to play recorded songs. They hired individuals who not only knew about music, but also had the gift of the gab to keep listeners entertained. These people became known as “disc jockeys”.
Why this term? In the U.S, vinyl records were called “discs”. As for the word “jockey”, you probably know it can be used both as a noun and a verb. The noun refers to a professional horse rider. When you “jockey a horse” what you are trying to do is steer or direct it into a winning position. Similarly, the disc jockey was trying to direct the taste of the public as far as music was concerned. By playing some songs repeatedly, he jockeyed (influenced) public taste in music. The records he played on the air sometimes became big hits. As time went by, the word “jockey” began to be used with individuals belonging to other professions: “plow” jockey (farmer), jet jockey (pilot), typewriter jockey (typist), etc.