Pronunciation: (pī'u mā'tur, pē'u), [key] Anat.
the delicate, fibrous, and highly vascular membrane forming the innermost of the three coverings of the brain and spinal cord. Cf. arachnoid (def. 6), dura mater.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.