If a hotdog is not a sandwich, what is it? Not saying I entirely agree that it is a sandwich, but if not that, what? Is it a sub/hoagie or it's own thing, sui generis?
To get (semi) serious for a second, this is the issue people can get into when discussing family-resemblance concepts, and using rigid definitional ideas ... because natural language does not have the formal rigidity of a symbolic logical system, let alone math.
It is for these reasons, claims such as "A hot dog is a sandwich" that we end up getting court being forced to make statements like, "“In this case we are called on to determine whether a cow is an uninsured motor vehicle under appellants’ insurance policy. We hold that it is not.” Why? Because for every pedant, there is a pedanter.
But to answer your question, I find that sandwiches to not be some overarching item that encompasses all foodtuffs, from deserts (ice cream sandwiches) to wraps, to burritos, to tacos, to lobster rolls, to open faced sandwiches, to massive cheeseburgers, to nachos, to sushi, and so on.
A sandwich is, to me, two slices of
bread and a filling in between them (that is not bread). Moreover, if you are prone to use a term that is other than a sandwich in referring to the item (such as taco, burrito, or even burger) then it is not a sandwich.
If you chop up your hot dog, and eat it between two slices of bread, then you have a sandwich. If not, you don't. And do you know how you tell? Very simple-
You are at the ballbark. You want to order a Fenway Frank. Or a Dodger Dog. Do you say, "Hey, Ima get me a hot dog. Anyone else want one?" Or do you ask who else wants ... a SANDWICH?
Yeah, I thought so. Usage, as always, is the #winner.
EDIT- the test should always be this- if you ask somebody, "Hey, do you want a sandwich?" when asking about the item ... if they are confused, then
it's not a sandwich.