dormer. Projecting framed structure set vertically on the rafters of a pitched roof, with its own roof (pitched or flat), sides (dormer cheeks), and a window set vertically in the front. It will often have a small gable or pediment (dormer-head) over the window if the roof is pitched at right angles to the main roof, but if the roof is a cat-slide it will have a flat top. Not to be confused with a lucarne rising directly over the eaves from the naked of the main wall below.

dor·mer / ˈdôrmər/ (also dormer window) • n. a window that projects vertically from a sloping roof. ∎  the projecting structure that houses such a window: the windowed dormer above the sink.

dormer