noun
oval window; fenestra ovalis; fenestra vestibuli
Anatomical term for the membrane-covered opening between the middle ear and the vestibule of the inner ear.
前庭窓は中耳と内耳の間にある小さな開口部です。
The oval window is a small opening between the middle ear and the inner ear.
From 前庭 (vestibule) + 窓 (window), a calque of the anatomical term 'oval window'.