Barbacan

Definition:

(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.

Compare barbacan with other words:

barbacan vs. barracan