Tuna fish sandwich

A tuna fish sandwich, known outside the United States as a tuna salad sandwich or a tuna sandwich, is a sandwich made from canned tuna—usually made into a tuna salad by adding mayonnaise, and sometimes other ingredients such as celery or onion—as well as other common fruits and vegetables used to flavour sandwiches. It is commonly served on sliced bread. Variations include the tuna boat and the tuna melt (served with melted cheese).

Source: Wikipedia