"one who jumps," 1610s, agent noun from jump (v.). In basketball, "jump-shot," from 1934. The meaning "basket on an elastic cord permitting a small child to push off the floor" is short for baby-jumper (1848).
article of clothing, 1853, in reference to a kind of loose jacket with sleeves, apparently from mid-17c. jump (n.) "short coat worn by men," also "woman's under-bodice," a word of uncertain origin. It is perhaps from French jupe "skirt" (see jupe) or from some notion in jump (v.). Meaning "sleeveless dress worn over a blouse" is from 1967, short for jumper-dress (1907).