ramparts

noun

1. 1

   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.

2. 2

   A defensive structure; a protective barrier; a bulwark.

3. 3

   That which defends against intrusion from outside; a protection.

4. 4

   (usually in the plural) A steep bank of a river or gorge.