| Citadel (n.) A fortress in or near a fortified city, commanding the city and fortifications, and intended as a final point of defense. Thesaurus Entries acropolis, bastion, beachhead, blockhouse, bridgehead, bunker, castle, donjon, fasthold, fastness, fort, fortress, garrison, garrison house, hold, keep, martello, martello tower, mote, motte, peel, peel tower, pillbox, post, rath, redoubt, safehold, strong point, stronghold, tower, tower of strength, ward |