Hot-dog is an American term that dates back to 1930 and derives from an American humorist's drawing representing a "teckel" (ancient Egyptian name which identifies the German dachshund short-haired) in the shape of a sausage.
It indicates a long and thin sandwich with a hot sausage and mustard. Hot dogs are extremely popoular in the United States and are in fact widely sold in snack bars and small kiosks.