| Acropolis (n.) The upper part, or the citadel, of a Grecian city; especially, the citadel of Athens. Thesaurus Entries bastion, beachhead, blockhouse, bridgehead, bunker, castle, citadel, donjon, fasthold, fastness, fort, fortress, garrison, garrison house, hold, keep, martello, martello tower, mote, motte, peel, peel tower, pillbox, post, rath, safehold, strong point, stronghold, tower, tower of strength, ward |