Origin: Latin suffix -ment
Battlement has 2 different meanings across 1 category:
a rampart built around the top of a castle with regular gaps for firing arrows or guns
In fortification: an indented parapet, formed by a series of rising members called cops or merlons, separated by openings called crenelles or embrasures, the soldier sheltering himself behind the merlon while he fires through the embrasure or through a loophole in the battlement.