Webster’s Revised Unabridged Dictionary · 1913
Dormer
Dor′mer (·mẽr), or Dor′mer win′dow (wĭn′dō), n. [Literally, the window of a sleeping apartment. F. dormir to sleep. See Dormant, a. & n.] (Arch.) A window pierced in a roof, and so set as to be vertical while the roof slopes away from it. Also, the gablet, or houselike structure, in which it is contained.