Tripe meat is made of the stomach and parts the intestine of various animals including cows, buffalo, sheep and cattle in particular.
Beef Tripe via kwout
A cow has four stomachs. The stomach walls of the first three are commonly sold as "tripe" and the fourth less commonly so. Some Americans hold tripe to be disgusting, but there are many famous recipes for it.
While it may not be the most popular part of the animal, tripe, the lining of the stomach, does provide a number of essential nutrients. See basic nutrition facts from SFGate.com.
Here are recipes for tripe and ways to prepare it shared by The Tripe Marketing Board.