Définitions
1.NounThe upper (and usually smaller) part (casement) of a window, often hinged a the top
2.NounAny glazing above a main window, partition or door, transom window
3.NounA skylight.
4.NounLight from above; toplighting.
5.Noun1 2 Nikolas Davies, Erkki Jokiniemi: Dictionary of Architecture and Building Construction, p. 388