Plural of casbah, a citadel or fortified settlement in a North African city, especially the old medina of Algiers.
From Arabic qasbah (fortress), which became casbah in French colonial usage. French spread this term through European languages.
The word 'casbah' became ultra-famous from the 1966 song 'Casbah Rock'—but most English speakers learned it from the song without knowing it's a real architectural term for ancient North African fortress-cities!
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