n.
The fine vascular membrane that closely envelops the brain and spinal cord under the arachnoid and the dura mater.
[Middle English, from Medieval Latin pia māter : Latin pia, tender + Latin māter, mother (translation of Arabic 'umm raqīqa : 'umm, mother + raqīqa, tender).]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
