Source : Webster's Revised Unabridged Dictionary (1913)

Fenestration \Fen`es*tra"tion\, n.
   1. (Arch.) The arrangement and proportioning of windows; --
      used by modern writers for the decorating of an
      architectural composition by means of the window (and
      door) openings, their ornaments, and proportions.

   2. (Anat.) The state or condition of being fenestrated.

Source : WordNet®

fenestration
     n 1: the arrangement of windows in a building
     2: surgical procedure that creates a new fenestra to the
        cochlea in order to restore hearing lost because of
        osteosclerosis