pizza-pie - 1935, from Italian pizza, originally "cake, tart, pie" http://dictionary.reference.com/etymology/pizza-pie

For the story of how pizza was introduced in the US: http://www.americanheritage.com/articles/magazine/ah/2006/2/...

As a Hoosier (a person from Indiana) I've always thought the same thing. We never called a pizza a pie. When I was young, though, I saw the term "pie" used in a Nancy Drew novel, and I've seen the phrase "pizza pie" as well. Obviously they're related, and equally obviously there's some regional variation, but ... whatever the region is, Indiana is outside it.

When the moon hits your eye like a big pizza pie? That's amoré.

When you're swimming in the sea and an eel bites your knee, that's a Moray.

When a guy's riding by on a bike in a tie, that's a Morman.

They're both round and relatively flat (in proportion to their diameter).

For "deep dish" pizzas especially they are even baked in a similar pan.

C'mon, it's not THAT much of a stretch.

Because when Marco Polo returned from China, he brought with him fantastic stories of meat pies, mythical pastries with the meat INSIDE of the bread.

How did it get in there? Nobody knows. Many tried, but none could discover the secret. Defeated, the Italians put the filling on top of the bread, and so invented pizza.

According to my dad, at least.

If you say "pie", you mean a pie. If you say "I'd like a 10-inch pie" in a pizza place, you mean a pizza pie. It's context.