Server at a soda fountain or ice cream shop. The name derives not from the attitude of teenage staff who might work there, but is a short form of soda jerker, simply an explanation of the job. In the 19th century, dispensing carbonated water required back-and-forth jerking motion on the dispenser levers to control the spray.

Short-order code probably originated with soda jerks, not short-order cooks, according to Harold W. Bentley's 1935 article "Linguistic Concoctions of the Soda Jerker" in American Speech.