define leptomeninges
Freebase(0.00 / 0 votes)Rate this definition: In medicine, leptomeninges is a term used to refer to the pia mater and arachnoid mater, two of the membranes that surround the brain and the spinal cord. The morphology of the brain in meningococcal meningitis is said to be covered by exudate on the surface of, and within the leptomeninges.