1. The loin yields the most tender and expensive cuts of beef-but not the most flavorful. The choicest portion is the tenderloin, which is exquisitely tender and lean. The top loin and sirloin aren't as tender.
2. The round is a kind term for the rear end of the carcass. Those muscles are well exercised, so round cuts tends to be a bit tougher and leaner than cuts from the loin. Round cuts do well if they're cooked with moist heat, and many of them can also be roasted, as long as they're not overcooked.
3. The brisket is a cut of meat from the breast or lower chest of ox or veal. The beef brisket is one of the nine beef prime cuts, though the precise definition of the cut differs internationally. The brisket muscles include the superficial and deep pectorals.
4. The flank is a beef steak cut from the abdominal muscles of the cow. A relatively long and flat cut, flank steak is used in a variety of dishes including London broil and as an alternative to the traditional skirt steak in fajitas. It can be grilled, pan-fried, broiled, or braised for increased tenderness.