Rampart [ˈram-pärt, ˈram-pərt]
1. Fortification, a protective barrier
2. Anything serving as a bulwark or defense
3. To fortify or surround with (verb)

● Usage:
Take the track to the left of the castle ramparts.
Yes, everyone watched as Ned's head was very clearly severed from his body and placed on a spike on the ramparts of King's Landing.
The city was ramparted and surrounded with a ditch.

First known use: 1536. Came from Middle French 'remparer' - 'to fortify'. From Old Occitan 'emparar', Old Provençal 'amparer, antparar', from Latin 'ante' - 'before' + 'parāre' - 'to prepare'.