Writing an opinion for the Supreme Court case Jacobellis v. Ohio, Justice Potter Stewart offered a definition of pornography that was also a lack of one: "I know it when I see it," he said.

​You could say, if you wanted to be slightly creepy about it, the same thing about sandwiches. We have a basic idea of what a sandwich is: two slices of bread with some tasty stuff in between them, just as the Earl of Sandwich so ingeniously envisioned back in the 18th century. But get past those basics for form, and the specifics of function can make things … tricky. Is a hot dog a sandwich? What about a wrap? What about a gyro? Has an open-face "sandwich," with its single slice of bread, been lying to us this whole time?

This is a sandwich.

For the most part, of course, none of those questions much matter. Good food is good food, no matter how you, er, slice it; whether you call a piece of bread that is smothered in pulled pork, cole slaw, and melted cheese a "sandwich" or something else won't change the fact that it is delicious. In other ways, though, the sandwich-not-sandwich thing is an important distinction. It affects how foods are regulated and labeled. It also affects how foods are taxed. In a story this summer, NPR's Elise Hu reported on New York State's Tax Bulletin ST-835 (TB-ST-835), a code that includes in its definition:

  • common sandwiches, such as:
    • BLTs (bacon, lettuce, and tomato sandwiches);
    • club sandwiches;
    • cold cut sandwiches;
    • grilled cheese sandwiches;
    • peanut butter and jelly sandwiches;
    • salad-type sandwiches (e.g., chicken, egg, ham, and tuna);
  • bagel sandwiches (served buttered or with spreads, or otherwise as a sandwich);
  • burritos;
  • cheese-steak sandwiches;
  • croissant sandwiches;
  • fish fry sandwiches;
  • flatbread sandwiches;
  • breakfast sandwiches;
  • gyros;
  • hamburgers on buns, rolls, etc.;
  • heroes, hoagies, torpedoes, grinders, submarines, and other such sandwiches;
  • hot dogs and sausages on buns, rolls, etc.;
  • melt sandwiches;
  • open-faced sandwiches;
  • panini sandwiches;
  • Reuben sandwiches; and
  • wraps and pita sandwiches.

There are many arguments to make against this liberal definition of the sandwich (a wrap? a buttered bagel? come on), but the most scandalous aspect of Hu's finding was this: New York State had decided that burritos are sandwiches. Which is an interpretation of "sandwich" that would likely raise the eyebrows even of Justice Stewart. (And also, by the way, an interpretation that goes against legal precedent: In a 2006 court case that involved Panera and Qdoba and thus revolved, delightfully, around the definition of a "sandwich"—Judge Jeffrey Locke ruled that "the term 'sandwich' is not commonly understood to include burritos, tacos, and quesadillas, which are are typically made with a single tortilla stuffed with choice filling of meat, rice, and beans." This was, he further ruled, "dictated by common sense.")

This is not a sandwich.

Sandwiches may vary greatly by culture and region and taste; still, we can do better than "we know them when we see them." So, in the name of definitional detente, here's what we've come up with: a four-point definition of the sandwich, based on a given food item's architecture and nutritional content and spatial orientation. There's certainly room for argument in it; there's certainly room for disagreement in it. The only thing there isn't room for is burritos.

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