n. & adj.
--n. Anat. (in full arachnoid membrane) one of the three membranes (see MENINX) that surround the brain and spinal cord of vertebrates.
--adj. Bot. covered with long cobweb-like hairs.
Etymology: mod.L arachnoides f. Gk arakhnoeides like a cobweb f. arakhne: see ARACHNID