Prime rib is a cut of beef that comes from the primal rib section of the cow, which is one of the nine primal cuts of beef. It is also known as a standing rib roast. The primal rib section resides on the forequarter of the cow under the front of the backbone. A whole prime rib can contain up to seven ribs. The first cut of prime rib comes from the hind of the standing rib roast near the loin, while the second cut comes from the front end of the standing rib roast near the chuck. The difference between prime rib and ribeye is in how the butcher cuts and prepares the two. When a whole prime rib is sliced into individual steaks, it becomes ribeye steaks. Therefore, a ribeye steak is a cut of meat from the same primal rib section as the prime rib. In summary, prime rib is a larger cut of beef that contains the ribeye area as well, while ribeye is a smaller portion of the rib roast that is cut before being cooked.