'Pia mater' definitions:

Definition of 'pia mater'

(from WordNet)
noun
The highly vascular innermost of the 3 meninges

Definition of 'Pia mater'

From: GCIDE
  • Pia mater \Pi"a ma"ter\ [NL., fr. L. pia (fem. of pius tender, kind) + mater mother.] (Anat.) The delicate and highly vascular membrane immediately investing the brain and spinal cord. [1913 Webster]