There are 8 USDA grades of beef. All of them considered fit for human consumption. They are:
Prime, Choice, and Select. These are your better cuts (prime being the best), used for steaks and by resturants. Sometimes has a stamp or seal from the USDA.
Standard and Commercial. Generic brand meat usually no grade is displayed or advertised.
Utility, Cutter, Canner. For ground beef, hotdogs, higher grade animal food, etc.