In English, "牛肚" is typically called "tripe." It comes from the lining of an animal's stomach, most often a cow or a pig. Some example sentences and translations are:

I love eating tripe. (我喜欢吃牛肚。)

Do you have any tripe dishes on the menu? (菜单上有没有牛肚菜？)

My grandmother used to make the best tripe soup. (我奶奶过去做最好吃的牛肚汤。)

The word "tripe" is thought to come from Old French "tripe" or Latin "tripes," both of which mean "guts" or "intestines."