Arachnoid

Part of speech: noun (n.)

1. The arachnoid membrane.

2. One of the Arachnoidea.

Part of speech: adjective (a.)

1. Resembling a spider's web; cobweblike.

2. Pertaining to a thin membrane of the brain and spinal cord, between the dura mater and pia mater.

3. Covered with, or composed of, soft, loose hairs or fibers, so as to resemble a cobweb; cobwebby.