Fenestration or fenestrate may refer to:
Fenestration (architecture), relating to openings in a building Fenestra, in anatomy, medicine, and biology, any small opening in an anatomical structure Leaf window, or fenestration, a translucent or transparent area in a plant leaf Perforate leaf, sometimes described as fenestrate, a leaf that develops large holes as it grows Fenestration, holes in the rudders of some ships, supposedly giving greater control
See also Defenestration, the act of throwing someone or something out of a window, also figuratively National Fenestration Rating Council, an American organization that evaluates the energy performance of fenestration products