n. In the early church, a doorkeeper; an ostiary (which see).n. In anatomy: The orifice of communication between the stomach and the intestine, by which the contents of the stomach pass into the intestine.n. The fold of mucous membrane, containing muscular fibers, which guards the pyloric orifice, or other contrivance for retarding or opposing the passage of food from the stomach into the intestine.n. The pyloric end or division of the stomach.n. In Hydrozoa, a valvular structure which separates the gastric from the somatic cavity in the siphonophorous hydrozoans.