* For a sweet pie, like an apple pie or a custard pie, πίτα (pita) is often used. However, πίτα generally refers to a flatbread or a thin pastry, so context is important.
* For a savory pie, like a meat pie, you might use πιτάκι (pitaki), which is a diminutive of πίτα and often implies a smaller pie, or a more descriptive phrase explaining the filling.
So, there's no single perfect translation. "Πίτα μήλου" (pita milou) would mean "apple pie", for example.