1. to surround with a rampart or fortification; to encircle with a defensive wall or barrier
Usage: formal; historical/military context

Examples

• The Roman army circumvallates the enemy city to cut off all supply routes.
• Medieval fortifications circumvallate the town center with thick stone walls.
• The general circumvallates the fortress to prevent any escape or reinforcement.
• Ancient engineers circumvallate settlements to provide protection from invaders.
• The defensive line circumvallates the strategic position on the hilltop.