Definition of: parietal

(pə·rī′ə·təl) adjective
1. Biol. Of, pertaining to, or forming the walls of any cavity in the body.
2. Of or pertaining to a wall.
3. Pertaining to the care of or residence within walls or precincts, as of a college.
4. Bot. Pertaining to or borne on a wall: said especially of the placentae or ovules borne on the wall of the ovary of a plant.
—noun
1. A parietal bone.
2. plural U.S. the rules that govern dormitory visitation for members of the opposite sex.