oriel

noun

1. a bay window, especially one cantilevered or corbeled out from a wall.
2. (in medieval architecture) a large bay window of a hall or chamber.

n.“large recessed window,” mid-14c., from Old French oriol “hall, vestibule; oriel,” of uncertain origin, perhaps from Medieval Latin oriolum “porch, gallery” (mid-13c.), perhaps from Vulgar Latin *auraeolum, dissimilated from aulaeolum, a diminutive of Latin aulaeum “curtain.” Despite much research, the sense evolution remains obscure.