n. In medieval architecture, an opening in the vault of a portal or passage, or in the floor of a projecting gallery, made for the purpose of hurling missiles, or pouring down molten lead, hot pitch, etc., upon an enemy essaying to enter or mine.n. The act of hurling missiles or of pouring burning liquids upon an enemy through apertures such as those described above.n. By extension, a machicolated parapet or gallery, or a projection supported on corbels, in imitation of medieval machicolated construction, without openings.