BARBACAN
barbican, barbacan
(noun) a tower that is part of a defensive structure (such as a castle)
Source: WordNet® 3.1
Bar"ba*can, n.
Definition: See Barbican.
Bar"bi*can, Bar"ba*can, n. Etym: [OE. barbican, barbecan, F.
barbacane, LL. barbacana, barbicana, of uncertain origin: cf. Ar.
barbakh aqueduct, sewer. F. barbacane also means, an opening to let
out water, loophole.]
1. ( Fort.) 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.
2. An opening in the wall of a fortress, through which missiles were
discharged upon an enemy.
Source: Webster’s Unabridged Dictionary 1913 Edition