'Dormer window' definitions:

Definition of 'dormer window'

From: WordNet
noun
The window in a gabled extension built to accommodate a window
noun
A gabled extension built out from a sloping roof to accommodate a vertical window [syn: dormer, dormer window]

Definition of 'Dormer window'

From: GCIDE
  • Dormer \Dor"mer\, or Dormer window \Dor"mer win"dow\, 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. [1913 Webster]