grenade (n.)
"small explosive shell," thrown rather than discharged from a cannon, 1590s, earlier "pomegranate" (1520s), from Middle French grenade "pomegranate" (16c.), earlier grenate (12c.), from Old French pomegrenate (see pomegranate). Form influenced by Spanish granada. So called because the many-seeded fruit suggested the powder-filled, fragmenting bomb, or from similarities of shape. See pomegranate. Much used late 17c., they went out of use 18c. but were revived 20c.