citizen:
(plural: ‘citizens‘; for the right pronunciation of this word, please click here)
a person who lives in a city;
a person who belongs to a particular country by birth, and has a right to live in that country, enjoying the rights and obeying the laws of that country;
a person who was not born in a particular country or his/her parents are not the citizens of that country, but lives in that country permanently by applying and getting the citizenship from the government,

citizens of the world
David Ortiz, the baseball celebrity, is by birth a citizen of Dominican Republic, Caribbean region, but he has changed his citizenship, and now he is a citizen of the USA.
Some critics argue that President Obama is not an American citizen because he was born in Kenya or some other country and that his parents are not American citizens.
Every citizen of a country has several rights he/she can enjoy, such as freedom to move, buy or sell his/her own property, do a job, get education, etc., and at the same time, every citizen has responsibilities, such as obeying the laws, paying the taxes, respecting the country, protecting the country, being good with other citizens, etc.

