n.1. A dish composed of fruit, meat, cheese, or other ingredients baked over, under, or surrounded by a crust of pastry or other dough.
2. A layer cake having cream, custard, or jelly filling.
3. Informal A pizza.
4. Something similar to or resembling pie: mud pie.
5. A whole that can be portioned out: "That would ... enlarge the economic pie by making the most productive use of every investment dollar" (New York Times).