| Meninges (n. pl.) The three membranes that envelop the brain and spinal cord; the pia mater, dura mater, and arachnoid membrane. Thesaurus Entries allantoic membrane, amniotic sac, arachnoid membrane, basement membrane, conjuctiva, eardrum, hymen, maidenhead, membrana serosa, membrana tympana, membrane, meninges, meninx, neurilemma, pellicle, pericardium, perineurium, pleura, serosa, tympanic membrane, tympanum, velum |