There are many who claim that a hot dog in any form is a sandwich and that, by extension, a Coney Dog is a sandwich as well. This claim runs against definitions in the Oxford English Dictionary.
A sandwich is defined by the Oxford English Dictionary as “(a)n item of food consisting of two pieces of bread with a filling between them, eaten as a light meal.” [ref] This is different from the Oxford definition of a hot dog as “(a) frankfurter, especially one served hot in a long, soft roll and topped with various condiments.” [ref] Even more telling is the Oxford definition for a frankfurter, which states “a small, cooked and smoked sausage of beef or beef and pork.” [ref] These latter definitions clearly describe a hot dog as “(a) frankfurter”, i.e. as the meat itself, without any type of bread product. Therefore, a hot dog on its own is not a sandwich in any form.
A Coney Island Hot Dog is then a hot dog, in a long, soft roll, with toppings. Oxford itself defines a Coney Dog as “(a) type of hot dog topped with chili con carne (without beans), raw onion, and mustard.” [ref] It’s the “long, soft roll” that makes the difference. Oxford also makes this differentiation in their definition of a Submarine Sandwich, i.e., “(a) sandwich made of a long roll filled with meat, cheese, and vegetables such as lettuce, tomato, and onions.” [ref] Here the item is called a sandwich in the definition, which does not occur in their definitions of either a hot dog nor a Coney dog.
Clearly, as there are not two slices of bread involved in the Oxford definition, Oxford states that a Coney Dog is not a sandwich, as opposed to other definitions within their work which explicitly state that a defined item is a sandwich.