dura mater UK /ˌdjʊə.ɹə ˈmeɪ.tə/US /ˈd(j)ʊɹ.ə ˌmeɪ.tɚ/ noun1 •The tough and inflexible outermost of the three layers of the meninges, enveloping the brain and spinal cord.Hmm, false membranes are adhering to the arachnoidian layer of the dura mater. I’m directing my gaze into a world of constant visibility. Where does it hurt? — 1997 formsdura maters · durae matres