pia ma·ter 
(mātər, mätər)
(mātər, mätər)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).]
- pro-choice
- pro-choicer
- proclaim
- proclaimer
- proclaim from the housetops
- proclamation
- proclamatory
- proclisis
- proclitic
- procliticization
- procliticize
- proclivity
- Procne
- procoagulant
- proconsul
- proconsular
- proconsulate
- proconsulship
- Procopius
- procrastinate
- procrastination
- procrastinator
- procreant
- procreate
- procreation