The term, "prime rib" was coined years before the USDA grading system that uses the descriptive terms such as: prime, choice, select or cutter, was established. The term prime rib tells the buyer that the roast was cut between the 6th and 12th ribs inclusive. This means you can have a prime rib roast from any grade of beef. This also means that roasts cut from the carcass containing ribs other than the 6th through 12th should be referred to as standing rib roasts.
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