The quiche thread reminded me we had this family argument at Christmas.

Me, my brotherinlaw and Mr slicky say a tart is pastry on the bottom, filling on top, maybe a lattice on top of that. A pie is pastry on bottom and top like.

My Grandma, whose baking knowledge I would otherwise submit to argued a pie has JUST A LID, and a tart has pastry bottom and optional top.

Who's right? We could fight but she's 86 or something...