mitrailleuse (n.)

kind of machine gun designed to discharge a concentrated rapid fire of small projectiles from a group of rifled barrels, 1870, from French mitrailleuse (19c.), from French mitraille "small missile," especially grape, canister, etc., fired at close quarters (14c.), originally "small coins," hence "old iron, scrap iron," then "grapeshot;" a diminutive of mite "a small coin" (see mite (n.2)). "For sense development it should be borne in mind that orig. guns used to be loaded with scrap iron" [Klein]. Especially of a type of gun introduced in the French army in 1868 and first used in the Franco-Prussian War.