(1):
(n.) One of the Arachnoidea.
(2):
(a.) Resembling a spider's web; cobweblike.
(3):
(a.) Covered with, or composed of, soft, loose hairs or fibers, so as to resemble a cobweb; cobwebby.
(4):
(a.) Pertaining to a thin membrane of the brain and spinal cord, between the dura mater and pia mater.
(5):
(n.) The arachnoid membrane.