civitas

Civitas, civitatis is third declension feminine, built from civis plus the abstract suffix -tas, the same suffix that gives libertas and veritas. Its senses run in that order: first the status of being a citizen, then the body of citizens taken together, and only last the town they happen to live in.

That gives the distinction against urbs. Urbs is the physical city, walls and streets and buildings; civitas is the community and its rights. Cicero granting somebody civitas is granting citizenship, not a town. The drift worth watching is medieval: by the time of the charters in this corpus civitas usually does just mean the town, and often specifically a town with a bishop, which is why French cité and Spanish ciudad mean what they do. Family: civis, civilis, civicus. English city, citizen, civic, civil, civilian, civilisation.