4. Whatever is arranged to drop, hang, or fall from an elevated position; also, a contrivance for lowering something; as: (a) A door or platform opening downward; a trap door; that part of the gallows on which a culprit stands when he is to be hanged; hence, the gallows itself. (b) A machine for lowering heavy weights, as packages, coal wagons, etc., to a ship's deck. (c) A contrivance for temporarily lowering a gas jet. (d) A curtain which drops or falls in front of the stage of a theater, etc. (e) A drop press or drop hammer. (f) (Mach.) The distance of the axis of a shaft below the base of a hanger.