crenellation (en)

(noun) the battlement of a castle or other building. / (noun) any of the embrasures alternating with merlons in a battlemen

stanchion (en)

(noun) an upright bar, post, or support (as for a roof or a ship's deck) / (noun) a device that fits loosely around the neck of an animal (as a cow) and limits forward and backward motion (as in a stall)