A lucarne is defined as a `small gabled opening in a roof or a spire`. ==Links== ...
dormer window
• (n.) A dormer window.
(from the article `dormer`) ...room.` Dormers are set either on the face of the wall or high upon the roof, and their roofs may be gabled, hipped, flat, or with one slope. A ...
a small window in a spire or roof
small dormer in a spire or tower roof. 
A canopied opening in a spire. Related Words: Spire, spirelet
Lu`carne' noun [ French, from Latin lucerna a lamp. See Luthern .] (Architecture) A dormer window. 
In architecture a lucarne is a dormer or garret window.
a dormer window.