1.NounA dish of ground meat (usually made from ground beef, although lamb, pork, veal, venison, poultry and seafood are also used) formed into a loaf shape, mixed with egg and breadcrumbs, then baked or smoked, and usually served in slices."For his meatloaf, he mixed the meat, eggs, chopped onion, breadcrumbs, tomato sauce and a can of beer according to the instructions, then diced in an apple he had lying around."