tegmen

noun (plural tegmina /-mənə/)

• a covering structure or roof of an organ, in particular.
• Entomology a sclerotized forewing serving to cover the hind wing in grasshoppers and related insects.
• Botany the delicate inner protective layer of a seed.
• (also tegmen tympani) Anatomy a plate of thin bone forming the roof of the middle ear, a part of the temporal bone.