If the definition doesnt convince you maybe the etymology will.
1610s, "native of Hamburg;" the meat product so called from 1884, hamburg steak, named for the German city of Hamburg, though no certain connection has ever been put forth, and there may not be one unless it be that Hamburg was a major port of departure for German immigrants to United States. Meaning "a sandwich consisting of a bun and a patty of grilled hamburger meat" attested by 1912. Shortened form burger attested from 1939; beefburger was attempted 1940, in an attempt to make the main ingredient more explicit, after the -burger had taken on a life of its own as a suffix (cf. cheeseburger, first attested 1938). The -burg is Ger. Burg "fort," in reference to the moated castle built there c.825; the first element is perhaps O.H.G. hamma "ham, back of the knee" in a transferred sense of "bend, angle," with reference to its position on a river bend promontory, or M.H.G. hamme "enclosed area of pastureland."
Clearly by 1912 it was an American sandwich made with hamburger meat. We have simply shortened it.
It's a burger...not a sandwich. Completely different terms that correspond to completely different expectations.
Following the hot dog analogy, would a stuffed pizza be considered a sandwich? You have two discrete slices of bread with a filling in the middle. I submit that it would not. I don't think the "two slices of bread and something in the middle" holds water, Merriam-Webster's be damned...
I've continued to think based on Fuzzy's statement. I am definitely still on team GlennBon and going to keep my answer as a firm "no" based on colloquial usage.
I would consider sandwiches and grinders (and mayyyybe hamburgers) like squares and rectangles. Sandwiches are rectangles. Sure the square/grinder is technically a rectangle, but do you look at a square and say, "hey look! A rectangle!" No. You don't.
If I say that I am eating a sandwich, this is what I am eating:
If I say that I am eating a grinder/sub, this is what I am eating:
And this is a hamburger. Not a hamburger sandwich:
Out of curiosity, I looked up the dictionary.com definition of “sport” since that always seems to be hotly contested. Within the definition, they give examples which include golfing, hunting, and fishing. Golfing is very much debatable, but you can’t tell me you have to be physically fit to be good at hunting or fishing.
I’m not really sure what the point of this was, other than sometimes dictionary definitions are whack.