meninges

This term refers specifically to the protective layers of the central nervous system. It is used almost exclusively in medical, anatomical, and pathological contexts, such as when discussing meningitis or cerebrospinal fluid dynamics. The word carries a clinical tone and is rarely encountered in general conversation outside of a healthcare setting.

Grammatically, this noun is a pluralum tantum, meaning it is used exclusively in the plural form to describe the collective set of membranes. Because it lacks a standard singular form in English, it cannot be counted as a single unit; instead, one must refer to a specific layer (like the dura mater) or use a partitive construction if referring to a single membrane.