Dictionary definition of citadel

The word comes from the Latin "civitatis" meaning "city" and "castellum" meaning "fortress".
Citadels were built during medieval times, and they were often the most important and heavily fortified structures within a city or town. They were designed to provide protection for the ruling elite, as well as for the general population in case of an attack. They were typically built with thick walls and towers, with features such as drawbridges, moats, and battlements.
Nowadays, many citadels are preserved as historical landmarks and tourist attractions. Some of them have been transformed into museums, art galleries, or hotels, and others are still used for military or other purposes.
In general, A Citadel is a fortress or fortified stronghold, typically located on high ground, designed to protect a city or town from attack, it was built during medieval times, and many of them are preserved as historical landmarks and tourist attractions.