If served on a split long roll it is a hot dog. If you cut the roll horizontally it becomes a sub. Serve three cocktail frankfurts crosswise on a round roll and it is a burger. Sliced and served between two slices of bread it the only way it becomes a sandwich. Unless you then toast it and transform it into a toastie, or toast it in a special press and turn it into a jaffle. All completely different meals.