1) Meninges 2) Meninx 
• (a.) Situated under the dura mater, or between the dura mater and the arachnoid membrane.
(sәb-doo´rәl) between the dura mater and the arachnoid.
Sub·du'ral adjective (Anat.) Situated under the dura mater, or between the dura mater and the arachnoid membrane. 
Type: Term Pronunciation: sŭb-dū′răl Definitions: 1. Deep to the dura mater. 2. Between the dura mater and the arachnoid mater. See: spatium subdurale
Subdural: Below the dura, the outermost, toughest, and most fibrous of the three membranes (meninges) covering the brain and the spinal cord. An subdural hematoma is a collection of blood beneath the dura.
outside the brain
[adj] - below the dura mater but above the arachnoid membrane of the meninges
adjective below the dura mater but above the arachnoid membrane of the meninges