What Is a Pie?

As with all things, one must start be defining the terms one using. I remembered today that I hadn't defined what a pie was or is.

According to the Oxford (British and World English) dictionary, a pie is "A baked dish of fruit, or meat and vegetables, typically with a top and base of pastry.

The American Heritage dictionary says:

1. A baked food composed of a pastry shell filled with fruit, meat, cheese, or other ingredients, and usually covered with a pastry crust.
2. A layer cake having cream, custard, or jelly filling.

Merriam-Webster defines pie as:

1. A meat dish basked with biscuit or pastry crust--compare to potpie.
2. A dessert consisting of a filling (as of fruit or custard) in a pastry shell or topped with pastry or both.

What's Cooking in America gives a fascinating history of pies which began as baked containers and weren't particularly edible. There were indeed animated pies--with things like birds and even people coming out. 

Then we have to round up terms that seem to refer to pie-like things such as a cobbler. Merriam-Webster defines a cobbler as (4) "A deep-dish fruit dessert with a thick top crust. A tart is "a dish baked in a pastry shell as in (a) a small pie or pastry shell without a top containing jelly, custard, or fruit or (b) a small pie made of pastry folded over a filling. A potpie is "a mixture of meat and vegetables that is covered with a layer of pastry and cooked in a deep dish.

American Heritage defines a tart as 1(a) "A pastry shell with shallow sides, not top crust, and any of various fillings. 1(b) Chiefly British "A pie."  A cobbler is "A deep-dish fruit pie with a thick top crust." 

The editors of Encyclopedia Britannica write: 

dish made by lining a shallow container with pastry and filling the container with a sweet or savoury mixture. A top crust may be added; the pie is baked until the crust is crisp and the filling is cooked through. Pies have been popular in the United States since colonial times, so much so that apple pie has become symbolic of traditional American home cooking. The typical American pie is round, 8–10 inches (20–25 cm) in diameter, 2–3 inches (5–8 cm) thick, and usually contains a sweet filling of fruit, custard, or a pastry cream. Some American specialties are pecan pie, pumpkin custard pie (traditionally served on Thanksgiving Day), lemon pie with a soft meringue topping, and shoofly pie, a Pennsylvania Dutch (see Pennsylvania German) pie with a rich filling containing molasses.

So then is pizza a pie? Is Boston Creme Pie a pie or a cake? Shepherd's pie uses mashed potatoes instead of a pastry. So pastry doesn't have to be part of a pie.