What makes a pie a pie?

Is it the crust? The circular shape? The way it’s cooked?

Most of the definitions I’ve read recently seem to agree that a pie must be baked and that it has to have a fruit or meat-and-vegetable filling of some sort, but several dictionary and encyclopedia entries sort of waffled a bit on whether a layer of pastry on the bottom, top, or both is necessary. There’s a whole cookbook’s worth of wiggle room in the words “typically” and “generally” and “usually.”

My wife whipped up a crustless quiche this morning to celebrate Pi Day, which seemed to satisfy my kids’ desire for a food properly befitting this most mathematical of days.

Our dinner plans involve taking and baking a pizza from a nearby shop, because pizza is totally a pie, right? I’ve always thought it could sort of slide into that definition, but I just learned of an argument that pizza is actually an open-faced sandwich! I’ve only recently started wrapping my head around the idea that some people consider a hot dog to be a sandwich, because it’s meat between two halves of bread. But pizza? Someone’s oven didn’t fully preheat on that idea.

If what you’re eating today is not obviously a pie, could you make an argument to justify it as one? Now that I think about it, there may be a case for French onion soup …

(Illustrations ®2018 Hatem Aly, from HOW TO FEED YOUR PARENTS)