citadel
1. A fortress or strongly fortified building in or near a city, used as a place of refuge.
2. An organization or institution which strongly defends a particular way of life or principle.
3. A stronghold or fortified place; a bulwark.
4. Etymology: from 1586, "fortress commanding a city", from Italian cittadella, diminutive (small version) of cittade, "city", from Latin civitatem.
citizen
citizenry
city
civic
civically
civics
civil
civilian
civilities
civility
civilization
civilize
civilized
civily