Pie is a baked dish typically made of pastry dough casing that contains a filling of various sweet or savory ingredients.
Other meanings of pie include:
1. In mathematics, π (pi) - the ratio of a circle's circumference to its diameter
2. Slang for "easy" or "simple" (as in "easy as pie")
3. A portion or share of something (as in "a piece of the pie")
4. In printing, mixed-up type (as in "pie the type")