A standing rib roast, also known as prime rib, is a cut of beef from the primal rib, which is one of the eight primal cuts of beef. The entire rib section comprises ribs six through 12 of the animal; a standing rib roast can comprise anywhere from two to seven ribs. It is given the name "standing" because it is most often roasted in a standing position, that is, with the ribs stacked vertically and the vertebral processes on the bottom. An alternative is to cook with the rib bones on the bottom and the vertebral processes removed for easier carving. A standing rib roast is an uncut number of bone-in rib steaks. An outstanding roast that should be served rare for optimal tenderness, favor, and juiciness. U.S. raised grass-fed beef.