1. a projecting parapet supported by corbels on a medieval castle; has openings through which stones or boiling water could be dropped on an enemy
2. An opening between the corbels which support a projecting parapet, or in the floor of a gallery or the roof of a portal, for shooting or dropping missiles upon assailants attacking the base of the walls. Also, the construction of such defenses, in general, when of this character. See Illusts. of Battlement and Castle.