Battlement

Definitions

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

Equivalents

CEFR level