witch window

noun1

1. •
   A window placed diagonally, with its long edge parallel to the roof, in the gable-end wall of a house (chiefly in Vermont in the United States), where a window oriented vertically or horizontally would not fit.

   • At the end of the room a witch window hung at an angle in the wall. She smiled. “Witch window. How quaint.” “Vermont is famous for them.[…]" — 2019