Is a hamburger considered a sandwich?
Solution 1:
No... I mean ... Yes ... I mean ... It's complicated.
Technically, of course a hamburger is a sandwich, by looking at a dictionary definition. Or to be pedantic (and give prelude to the complication), those things called 'hamburger' include all those properties that are defined and given the label 'sandwich'.
But what something 'is' and what something is 'called' and what its 'name' is (as Lewis Carroll said) are not (not necessarily) the same.
But that's almost too technical itself. A peanut is not a nut. A cardinal is a bird but doesn't have to have bird in its name to be a bird. A penguin is a bird even though many definitions of bird include 'flying'. Birds are now known to be dinosaurs, but that is a recent discovery (just like how at one time whales were considered fish).
The thing about 'technically', we don't normally use words that way. Is a cucumber a vegetable or a fruit? It's certainly a vegetable, formally or informally. But is it a fruit? It's not put in the fruit section with the apples and oranges and watermelon (when technically it is closely related to watermelon). No, a cucumber is considered a vegetable because it is green and not sweet, a lot like lettuce and celery.
Back to hamburger. So technically, yes, a hamburger is a sandwich, a very particular kind of sandwich. It has a lot of things unlike most sandwiches (a hot, grilled layer; a bun rather than sliced bread).
But, informally, it just doesn't seem like a sandwich. A BLT or chicken salad sandwich or corned beef on rye (mustard, no mayo) or even a grilled cheese all look like a usual sandwich. But a hamburger does not. There are many things about a hamburger (how it is prepared, where you can buy one, cultural associations) that are just not like a canonical sandwich.
So technically, yes, a hamburger is a kind of sandwich.
But if you did not include #5, the picture of a hamburger, in your answers, I'd say you're more like a human, and the robot would have included #5 because it is simple-mindedly rule based.
Solution 2:
YES.
Any item consisting of a filling served between 2 pieces of bread is a sandwich.
Merriam-Webster says:
Sandwich: 1a : two or more slices of bread or a split roll having a filling in between
Hamburger: 2: a sandwich consisting of a patty of hamburger in a split typically round bun
dictionary.com says:
hamburger: a sandwich consisting of a cooked patty of ground or chopped beef, usually in a roll or bun, variously garnished.
wikipedia says:
A hamburger (also called a beef burger, hamburger sandwich, burger or hamburg) is a sandwich consisting of one or more cooked patties of ground meat, usually beef, placed inside a sliced bun
The Hamburger is such a common sandwich that it no longer needs to have the word "sandwich" specified; it qualifies as its own sub-class.
If I were presented with that CAPTCHA, I'd select items 3, 4, and 5 as sandwiches.
Solution 3:
Yes, in the most literal sense
As noted in comments, burgers are a sub-category of sandwiches, which is why menus often list them separately - listing only sandwiches does not necessarily connote that they serve burgers, and listing only burgers does not connote that they serve non-burger sandwiches.
Solution 4:
Yes, it is a type of sandwich, thus it is a sandwich. It is even ruled by a judge in New York Supreme Court in 1980:
A New York Supreme Court judge has ruled that a hamburger is a sandwich.
"Defendant's narrow viewpoint that a 'hamburger is a hamburger' and not a sandwich is only true where a person would order 'beef ground' without the bread," Justice William Underwood wrote in a 12-page decision released June 12.
Toledo Blade - Jun 26, 1980
Today, it is not usually called a sandwich but I usually hear it called (or I call it) a sandwich in fast-food restaurants when you want to buy just the sandwich instead of a meal. However, you can call it a burger also.
OED entry for burger:
A familiar shortening of Hamburger n. Also used as a terminal element, e.g. in beefburger, porkburger, etc., usu. denoting a roll, sandwich, etc., containing the foodstuff specified in the first element. orig. U.S.
The word Hamburger also appears in Hamburger Steak (same as Hamburg Steak) and it is also a kind of sausage; but today, it is used commonly for a hamburger sandwich. In the past, the phrase hamburger sandwich was more common than it is used today and OED has an example from 1943:
She held a pair of..gloves in one hand and a hamburger sandwich in the other.
R.A.F. Jrnl. Aug. 10
The earliest citation for hamburger sandwich I could find is from 1902:
To start the thing off right, I ate a hamburger sandwich, carefully eliminating the gravel and other foreign substances as I came to them.
Desmos of Delta Sigma Delta, Volumes 9-11
Google Ngram result for hamburger sandwich between 1900-2000:
Solution 5:
I'll take the roundabout way of answering.
Is a tomato a fruit or a vegetable? The answer is different depending on if you're asking botanically (a fruit) or culinarily (a vegetable). The same is true for other fruits as well, such as a cucumber. A peanut is culinarily nut, but botanically it is a legume (related to peas and beans).
Likewise, a hamburger is culinarily different from a sandwich - you'll see it listed separately on menus and it's often referred to differently, especially when there are other sandwich options - but it's still a sandwich.
When I'm ordering a burger from a fast food place, they'll often say "do you want the combo, or just the sandwich". So it is referred to that way in specific circumstances.