The dura mater, or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for keeping in the cerebrospinal fluid. The name "dura mater" is derived from the Latin "hard mother" or "tough mother", (translation of Arabic umm al-dimagh as-safiqa) and is also referred to by the term "pachymeninx" (plural "pachymeninges"). The dura has been described as "tough and inflexible" and "leather-like".