stronghold
noun
[ ˈstrɒŋhəʊld ]
• a place that has been fortified so as to protect it against attack.
• "their mountain strongholds fell to enemy attack"
Similar:
fortress,
fort,
castle,
citadel,
garrison,
keep,
tower,
hold,
donjon,
bunker,
fastness,
• a place where a particular cause or belief is strongly defended or upheld.
• "the island is a stronghold of the Gaelic language and culture"
