fen·es·tra·tion 
(fĕn′ĭ-strāshən)
(fĕn′ĭ-strāshən)n.
1. The design and placement of windows in a building.
2. An opening in the surface of a structure, as in a membrane.
3. The surgical creation of an artificial opening in a bone, as in the inner ear so as to improve or restore hearing.