batwing: one of a pair of swinging doors (as at the entrance to a western saloon)
swing door: a door that swings on a double hinge; opens in either direction
vasopressin: hormone secreted by the posterior pituitary gland (trade name Pitressin) and also by nerve endings in the hypothalamus; affects blood pressure by stimulating capillary muscles and reduces urine flow by affecting reabsorption of water by kidney tubules