Pronunciation: (u-rak'noid), [key]
1. resembling a spider's web.
2. of or belonging to the arachnids.
3. Anat.of or pertaining to the arachnoid membrane.
4. Bot.formed of or covered with long, delicate hairs or fibers.
1. an arachnid.
2. Anat.the serous membrane forming the middle of the three coverings of the brain and spinal cord. Cf. dura mater, meninges, pia mater.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.