A kasbah (Arabic: القصبة al-qaṣbah) or qassabah is a type of medina, Islamic city, or fortress (citadel).
It was a place for the local leader to live and a defense when a city was under attack. A kasbah has high walls, usually without windows. Sometimes, they were built on hilltops so that they could be more easily defended. Some were placed near the entrance to harbors.
Having a kasbah built was a sign of wealth of some families in the city. Almost all cities had their kasbah, this building being something necessary for the city to survive. When colonization started in 1830, in northern Algeria, there were a great number of kasbahs that lasted for more than 100 years.
The word kasbah may also be used to describe the old part of a city, in which case it has the same meaning as a medina quarter. The Spanish word alcazaba is a cognate naming the equivalent building in Andalusia or Moorish Spain. In Portuguese, it derived into the word alcáçova. In Turkish and Urdu the word kasaba refers to a settlement larger than a village but smaller than a city; in short, a town.