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.

Source: https://en.wiktionary.org/wiki/rampart, https://en.wiktionary.org/wiki/ramparts