A dormer or dormer window is a window that is built upright in a sloping roof. a window built into a roof, so that it sticks out from the roof skylight (dormeor , from dormir; DORMANT). Window set vertically in a structure that projects from a sloping roof. It often illuminates a bedroom. In the late Gothic and early Renaissance periods, elaborate masonry dormers were designed. Dormers were used along with the mansard roof to defy a Parisian law limiting buildings to six stories; the seventh story was called a garret (or attic) and was made habitable by the dormer. See also gable
A gable or shed-like projection from the inclined surface of a roof which provides attic light, ventilation and additional head room, contains one or more windows