jump [E16th] Like bump [M16th] and thump [M16th], jump was probably formed because it ‘sounded right’, and seemed to express the sound of feet hitting the ground. It was first used around 1500. To jump the gun [M20th], or act too soon, comes from the idea of an athlete starting a race a split-second before they hear the starting gun. A jumpsuit was a term first used in the USA in the 1940s for the outfit worn by parachutists when making their jumps. Jumper [M19th] is unrelated. In the 19th century it was a loose outer jacket worn by sailors and is now a woollen jersey in UK English, but a style of dress in the USA. It may come from Scots jupe, ‘a loose jacket or tunic’, which in turn came through French from Arabic jubba.