battlement

noun

Etymology: From Middle English batilment, from Old French bataillement, earlier bastillement (“fortification”), from bastillier (“to fortify, to equip with battlements”), from bastille (“fortress”) (see bastion). By surface analysis, battle + -ment.

1. 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.

   “Towers, and battlements it sees Bosom'd high in tufted trees, Where perhaps some beauty lies, The cynosure of neighbouring eyes.”

2. Any high wall for defense.
3. The towering roof of heaven.