pickup (n.)

also pick-up, "that which is picked up," 1848; see pick up (v.). As "act of picking up" from 1882. Meaning "capacity for acceleration" is from 1909; that of "recovery" is from 1916. In reference to a game between informal teams chosen on the spot, from 1905; as an adjective, "composed of such things as are immediately available," by 1859.

Meaning "small truck used for light loads," 1937, is shortened from pickup truck (pickup body is attested from 1928). The notion probably being of a vehicle for use to "pick up" (feed, lumber, etc.) and deliver it where it was wanted.