An oeil-de-boeuf, also œil de bœuf and sometimes anglicized as ox-eye window or bull’s-eye window, is a relatively small oval or circular window, typically for an upper storey, and sometimes set in a roof slope as a dormer, or above a door to let in natural light.
It has glazing bars (bars framing the panes of glass) as spokes radiating outward from an empty hub, or circular centre.