Ask FunTrivia strives to be the most accurate and complete source for answers to trivia questions on the web. Please cite all facts with citation links or references from trustable sources. Editors continuously recheck submissions and claims.
Definition of arachnoid. 1  1 : of or relating to a thin membrane of the brain and spinal cord that lies between the dura mater and the pia mater. 2  2 : covered with or composed of soft loose hairs or fibers.
medical Definition of allantois plural allantoides play \ Ëal-Én-ËtÅ-É-ËdÄz, Ëal-Ëan-\ : a vascular fetal membrane of reptiles, birds, or mammals that is formed as a pouch from the hindgut and that in placental mammals is intimately associated with the chorion in formation of the placenta