subarachnoid space

English Thesaurus

1. a space in the meninges beneath the arachnoid membrane and above the pia mater that contains the cerebrospinal fluid (noun.body)

hypernym	:	space,
definition	:	an empty area (usually bounded in some way between things) (noun.shape)

part meronym	:	meninges, meninx,
definition	:	a membrane (one of 3) that envelops the brain and spinal cord (noun.body)