The round primal is the lean, mostly boneless section of beef from the animal's rear leg, one of the primal cuts a carcass is divided into during butchering. Because this area does a lot of work supporting the animal's weight, its muscles are lean with little fat marbling, and it's broken down further into cuts like top round, bottom round, eye of round, and sirloin tip. Its leanness and dense muscle fiber stay tough unless cooked with moist, slow methods -- braising, stewing, or slow roasting -- as in pot roast or Swiss steak. It's less prized than better-marbled primals like the rib or loin, but its affordability makes it a common choice for deli roast beef and for cuts sliced thin for sandwiches or stir-fries.