1) Barbican 2) Tower 1) Barbican 
• (n.) See Barbican. • (n.) A tower or advanced work defending the entrance to a castle or city, as at a gate or bridge. It was often large and strong, having a ditch and drawbridge of its own. • (n.) An opening in the wall of a fortress, through which missiles were discharged upon an enemy.
Bar'ba·can noun See Barbican .