Fruit pies are made from fruit (obviously). Crust and fillings are usually cooked together.
Nut pies are filled with nuts and a sugar-based mixture. Crust and fillings are usually cooked together. Nut pies usually have no top crust.
Cream pies are made from a pudding, gelatin, or mousse - usually poured into a pre-baked crust. Cream pies usually have no top crust.
Refrigerator pies (also known as icebox pies or Jell-O pies) are similar to cream pies, but made from gelatin-like fillings poured into a pre-baked crust and chilled to set. Refrigerator pies were made popular during the Great Depression along with other dishes that require no baking. Refrigerator pies usually have no top crust.
Custard pies are filled with raw custard poured into a raw crust, then both are baked together. Custard pies usually have no top crust.
Savory pies contain fillings such as steak, cheese, steak and kidney, minced beef, or chicken and mushroom. A common savory pie is cottage pie, also known as shepherd's pie, refers to a meat pie with a crust made from mashed potato.
Pizza pie is a world-popular dish of Italian origin, made with an oven-baked, flat, generally round bread that is often covered with tomatoes or a tomato-based sauce and mozzarella cheese. Other toppings are added according to region, culture, or personal preference. Originating as a part of Italian cuisine, the dish has become popular in many different parts of the world. The term “pizza pie is dialectal, and pie is used for simplicity in some contexts. In some regions, like Chicago, the term "pie" refers strictly to deep-dish, while in other regions "pie" refers to any form of pizza.
Pi (or π) is a mathematical constant whose value is the ratio of any circle's circumference to its diameter in Euclidean space. It is approximately equal to 3.1415926535897 in the usual decimal notation. Its decimal representation never ends or repeats. To calculate the circumference of your pie, multiply π by twice the radius. To find the surface area of the top crust, multiply π by the square of the radius.
What is pie?
Pie is the Pie Maven's favorite dessert. More specifically, pie is a baked dish which is usually made of a pastry dough shell that covers or completely contains a filling of various sweet or savory ingredients. Pies can be either "filled", where a dish is covered by pastry and the filling is placed on top of that, "two-crust," with the filling completely enclosed in the pastry shell , or "top-crust," where the filling is placed in a dish and covered with a pastry top before baking (less common). Don't be fooled by imposters - many sweet pastries call themselves "pie" even though they aren't, such as Moon Pies, Eskimo Pies, and Boston Cream Pie.
Pies can be a variety of sizes, ranging from bite-size pies to larger sizes designed for multiple servings. The typical American pie is round, 8–10 inches in diameter, 2–3 inches thick, and usually contains a sweet filling of fruit, custard, or a pastry cream.
As with any rule, there are exceptions. But if it has a crust and you cut it in slices, it's probably a pie
”It is utterly insufficient (to eat pie only twice a week), as anyone who knows the secret of our strength as a nation and the foundation of our industrial supremacy must admit. Pie is the American synonym of prosperity, and its varying contents the calendar of the changing seasons. Pie is the food of the heroic. No pie-eating people can ever be permanently vanquished.”
EDITORIAL, New York Times, 1902, In response to an Englishman’s suggestion that Americans should reduce their daily pie eating to two days per week.
