Definition of potpie:
(n) :
(US) A pie, having pastry sides and bottom and (usually also) top, and filled with savory fillings, such as meat, root vegetables, or (often) both.
(n) :
Especially, such a pie that is small, that has crust made entirely of flaky pastry, and that is baked in its own pie tin, usually for one person (single-serve).
(n) :
(US, regional) A dish of meat and vegetable stew with dumplings.