The lining of the stomach of cattle or sheep, but particularly the former. These animals actually have four different stomachs, so tripe is available either quite smooth or honeycombed. Tripe is nearly always sold blanched and partly cooked, but it still needs further long, slow cooking. This is usually preceded by a second blanching, in order to freshen the flavour.
One of the classic accompaniments to tripe is onions, whether in the English tripe and onions or the French tripes à la Lyonnaise. In Italy, tripe is often cooked with tomatoes or served in a tomato sauce; in Nice, in the south of France, tripe might be cooked with onions, tomatoes, garlic and white wine.