A pie is a dish of food, covered (often top and bottom) with a pastry crust. Normans and Franks were especially fond of meat pies and other pastries.
In Europe, meat pies are often a staple meal. In North America, pies are usually filled with sweet fruit preserves and served as a dessert. Small dessert pies are often called tarts.
Canadians tend to refer to meat pies as tortierre, or simply "torts", and dessert pies as "pies".