The towering roof of heaven.
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.
Any high wall for defense.
A strong fortress that sits high above a city.
A stronghold or fortified place.
An armoured portion of a warship, housing important equipment.
A Salvation Army meeting place.