A long deli sandwich is a type of sandwich made with cold cuts, cheese, and condiments. The term 'long deli sandwich' is often used to refer to a sub sandwich, which is a type of sandwich made on a long roll of Italian or French bread. Sub sandwiches are typically filled with meats such as ham, salami, and turkey, as well as cheese, lettuce, tomato, onion, and condiments such as mayonnaise and mustard.