Rampart
WordNet
noun
(1) An embankment built around a space for defensive purposes
"They stormed the ramparts of the city"
"They blew the trumpet and the walls came tumbling down"
WiktionaryText
Noun
- A defensive mound of earth or a wall with a broad top and usually a stone parapet; a wall-like ridge of earth, stones or debris; an embankment for defensive purpose.
- A defensive structure; a protective barrier; a bulwark.
- That which defends against intrusion from outside; a protection.
- A steep bank of a river or gorge.