Common Law Definition [change]
Citizen - a member of a group membership of Sovereign People that have Equal Rights, Liberty, Freedom, who consent to form and maintain a Government that protects these rights. The Government serves to admit & exile people from this citizenship/Vessel, in order to hold/protect these Rules/Rights.
Natural Born Citizen People born in a Government Border, who's parent also belong to, can become a Natural born Citizen.
Naturalized Citizen - People can also be naturalized citizens, if one was born/belongs in one Government but switches to a citizen of another Government, they are a naturalized citizen of the current Government, and lose prior membership with the other Government.
Dual Citizen People who consent to belong to more than one Government, with approval of both Government. People who consent to one Government but move and reside to another Government, with approval of both Governments. People who's parents Belong to a different Government than the Child's Natural Born Location, with approval of both Governments.
Judicial Legal Opinion [change]
See Black's Law Dictionary for a legal language.
Actor Peter Lorre was born 1904 in Hungary. In the 1940s, he moved to the United States and became a citizen of the United States. Lorre was born a Hungarian citizen and later became a naturalized United States citizen.
Someone who lives in a smaller area like a city can also be called a citizen of that city.