Etymology

Anglo-French, from (spelling alterated by influence of denizen), from Old French citeain, from cite, in medieval usage a cathedral town, but origininally meaning any settlement, regardless of size, from earlier citet, itself from civitas "citizenship, community of citizens", from civis "townsman, citizen" from a Proto-Indo-European base *kei- "to lie, homestead."

Noun

1. A person that is a legally recognized as a member of a state, with associated rights and obligations.

   When the rebellion broke out, the United States promptly evacuated its citizens from the area.

2. A member of a state that is not a monarchy; used as antonym to subject.
3. A person that is a legally recognized resident of a city or town.
4. A resident of any particular place to which the subject feels to belong.

   Citizen of the World: The Life of Pierre Elliott Trudeau - a book written of the former Canadian prime minister by John English, 2007.

5. A civilian, as opposed to a soldier, police officer etc.