'Fenestration' definitions:

Definition of 'fenestration'

noun

The arrangement of windows in a building

noun

Surgical procedure that creates a new fenestra to the cochlea in order to restore hearing lost because of osteosclerosis

From: GCIDE

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. [1913 Webster]
2. (Anat.) The state or condition of being fenestrated. [1913 Webster]