How do you spell Hannukah?
1870 in the anatomical sense, noun of action from Latin fenestrare, from fenestra "window, opening for light," perhaps from Etruscan. Meaning "arrangement of windows" is from 1846. Related: Fenestrated.
fenestration fen·es·tra·tion (fěn'ĭ-strā'shən)
An opening in the surface of a structure, as in a membrane.
The surgical creation of such an opening.
The surgical creation of an artificial opening in the bony part of the inner ear to improve or restore hearing.