B2
a person who is a member of a particular country and who has rights because of being born there or because of being given rights, or a person who lives in a particular town or city:
The interests of British citizens living abroad are protected by the British Embassy.
He applied to become an American citizen.
The citizens of Moscow woke up this morning to find they had a new government.
Old people are just treated like second-class citizens (= unimportant people).
He reassured people that law-abiding citizens (= people who do not break the law) would have nothing to fear from the enquiries.