noun
citadel
SIT-uh-dul/ˈsɪtədəl/
A fortified stronghold defending a city.
The stone citadel rises above the city, protecting it from the surrounding hills.

Etymology
The pieces give the image of a “little city.” This diminutive city-name came to designate a fortress commanding a city or protecting an important place.
In context
left a Macedonian Garrison there in the Citadel the name of the Citadel was cadmia
More examples
- Defenders retreated to the citadel.
- The university became a citadel of independent thought.
- They attacked the movement's strongest intellectual citadel.
Forms
citadel · citadels
Similar words
- fortress
- Fortress is a general fortified stronghold; citadel commonly defends or dominates a city.