[fe.nes.tra] n, pl -trae [NL, fr. L, window] (ca. 1737) 1: a small anatomical opening (as in a bone): as a: an oval opening between the middle ear and the vestibule having the base of the stapes or columella attached to its membrane--called also fenestra ovalis , fenestra vestibuli , oval window b: a round opening between the middle ear and the cochlea--called also fenestra cochleae, fenestra rotunda, round window
2: an opening cut in bone -- fe.nes.tral adj