From Longman Dictionary of Contemporary Englishfortressfor‧tress /ˈfɔːtrɪs $ ˈfɔːr-/ ●○○ noun [countable] PMTBBa large strong building used for defending an important place
Examples from the Corpus
fortress• Its origins are lost in antiquity but the Rock has probably ben used as a fortress from the Iron Age.• Without relationships, a man could be a fortress within himself, dedicated to a career and a dream.• Yet another fortress stands on a promontory only half a mile away.• The last hundred feet of elevation form a near-vertical cliff, effectively turning the mesa into an imposing dark fortress.• Their mountainous homeland with its fortress valleys was a near impregnable base from which to sally forth.• Some of the more interesting pubs are along the Grassmarket, just below the fortress.• Now she saw a different, more pleasing aspect of the fortress.• Only thirty succeeded in arriving at the gates of the fortress of the legendary Simorgh.Origin fortress (1300-1400) Old French forteresse “strong place”, from Latin fortis “strong” 