cit·a·del 
/ˈsɪtədl̟/ noun
plural cit·a·dels /ˈsɪtədl̟/ noun [count] : a castle or fort that in past times was used to protect the people of a city if the city was attacked
▪ We visited a medieval citadel in Italy. — often used figuratively ▪ The magazine has become a citadel [=stronghold] of liberalism/conservatism. ▪ the citadels of power ◊In the U.S., The Citadel is the name of a well-known military college.
▪ We visited a medieval citadel in Italy. — often used figuratively ▪ The magazine has become a citadel [=stronghold] of liberalism/conservatism. ▪ the citadels of power ◊In the U.S., The Citadel is the name of a well-known military college.
