Sub·a·rach·noid space n. The space between the arachnoid membrane and pia mater that is filled with cerebrospinal fluid and contains the large blood [more]Subarachnoid space - Community and Resources
Noun 1. a space in the meninges beneath the arachnoid membrane and above the pia mater that contains the cerebrospinal fluid (hypernym) space (part-holonym) meninx, meninges