Carnivores rejoice! It’s National Prime Rib Day

In honor of this marbled day, we offer a prime primer in meaty semantics.

Prime rib refers to a cut of meat -- officially called a standing rib roast. You know it. You've eyed it on menus. You've bragged about it amongst friends.

Any meat labeled "USDA Prime" refers to itsquality. However, just because it's prime rib doesn't necessarily mean it boasts the highest rating of prime grade. Of all the beef produced in the US, less than 2 percent is certified as USDA Prime. How to make the grade? Basically the higher the ratio of marbling and the younger the beef, the higher the grade. The fat marbling determines tenderness, juiciness and flavor. Therefore USDA Prime Grade has the highest rating of a combined high ratio of marbling with the youngest maturity of beef.

Is your mouth watering for any kind of prime meat you'll be able to get your hands on on the way home from work? Try it with this recipe for prime rib with horseradish sauce.