A hamburger (also burger for short) is a sandwich consisting of one or more cooked patties of ground meat, usually beef, placed inside a sliced bread roll or bun. The patty may be pan fried, grilled, smoked or flame broiled. Hamburgers are often served with cheese, lettuce, tomato, onion, pickles, bacon, or chiles; condiments such as ketchup, mustard, mayonnaise, relish, or "special sauce"; and are frequently placed on sesame seed buns. A hamburger topped with cheese is called a cheeseburger.
Some establishments serving hamburgers also serve chicken sandwiches, giving customers an alternative to beef.
Such a sandwich may also be called "chicken on a bun" or "chicken burger" in many countries,
and is served on a hamburger bun with similar condiments and toppings as found on hamburgers.
While most chicken sandwiches in this context usually use fried or grilled chicken breasts,
a chicken burger may also be made of a grilled or fried patty of ground chicken.
