A patty, in American, Canadian, South African, Australian and New Zealand English, is a flattened, usually round, serving of ground meat or meat alternatives. The meat is compacted and shaped, cooked, and served.
Patties can be eaten with a knife and a fork in dishes like Salisbury steak, but are typically served in a sort of sandwich called a "burger", or a hamburger if the patty is made from ground beef. The patty itself can also be called a burger, whether or not it is served in a sandwich, especially in the United Kingdom and Ireland, where the term "patty" is rarely used.
Similar-shaped meat cakes not made from ground beef may also be called "burger": "turkey burgers" or "fishburgers" may be made from reshaped mechanically separated meat. Sometimes burgers are breaded. Veggie burger patties are made without meat, usually of soy, but also often of other beans and occasionally of other mixed vegetables.
In Ireland, traditional chippers often serve batter burger (a beef-based patty dipped in batter and deep fried) or spice burger (a savory patty made with a proprietary recipe of meats and spices). These are served in a greaseproof paper bag and eaten with the hands.
In India, a patty may refer to either a vegetarian (potato for example) or non-vegetarian (chicken, meat etc.) burger filling, or to a sweet or savory puff pastry turnover which is a common street food in many parts of the country.
With mass-produced patties, it is not uncommon to find them with seemingly abnormal shapes or a bumpy perimeter. These groove-like bumps are caused by the machine that forms the patties. They are used in production to keep the patties in line, so they will not fall off the assembly line, and can be manipulated by the various machines. In other boxed patties, small punctures can be seen in the top and bottom sides of the patty. These punctures are there for similar reasons.