arachnoid

The American Illustrated Medical Dictionary · 1913 · p. 5

(ar-ak’noid) (Gr. dpaxrn spider + <ld0s form]. 1. Resembling a spider’s web. 2. delicate membrane interposed between the nis mater and the dura mater of the brain and spinal cord, being separated from the dura mater by the subarachnoid space.