Tripe is not often available in the US supermarkets. When we saw some at our local Stop & Shop we had to get it.
Tripe is the stomach of a cow. It is normally washed, boiled and bleached before sale. In this case we found the reticulum honeycomb and pocket tripe.
Tripe can have a very unpleasant taste. Iin the UK it is often cooked in milk and served with onions giving it a ‘barnyard’ aftertaste. We had eaten tripe at Per Se in NYC and I remember being served it in South Africa.