originaly, a soldier who carried and threw grenades; afterward, one of a company attached to each regiment or battalion, taking post on the right of the line, and wearing a peculiar uniform. in modern times, a member of a special regiment or corps; as, a grenadier of the guard of napoleon i. one of the regiment of grenadier guards of the british army, etc.-any marine fish of the genus macrurus, in which the body and tail taper to a point; they mostly inhabit the deep sea; -- called also onion fish, and rat-tail fish.-a bright-colored south african grosbeak (pyromelana orix), having the back red and the lower parts black.