Hamburger "patty" is rarely used, or the term can even refer simply to ground beef. The term may be prefixed with the type of meat or meat substitute used, as in "turkey burger", "bison burger", or "veggie burger". Hamburgers are sold at fast-food restaurants, diners, and specialty and high-end restaurants (where burgers may sell for several times the cost of a fast-food burger, but may be one of the cheaper options on the menu). There are many international and regional variations of the hamburger. The term "hamburger" originally derives from Hamburg, Germany's second-largest city. In German, "Burg" means "castle", "fortified settlement"
Hamburger some Australian themed pubs even kangaroo burgers can be purchased. These burgers are served in a similar way to the traditional hamburger but are sometimes served with a different sauce including redcurrant sauce, mint sauce and plum sauce. In the early 21st century "premium" hamburger chain and independent restaurants have arisen, selling burgers produced from meat stated to be of high quality and often organic, usually served to eat on the premises rather than to take away. Chains include Gourmet Burger Kitchen, Ultimate Burger, Hamburger Union and Byron Hamburgers in London. Independent restaurants such as Meatmarket and Dirty Burger developed