公民 (gōng mín) refers to a citizen in the legal/political sense — a person with rights and duties under a country's laws. It is distinct from 市民 (shì mín), which means 'city resident' (a geographic/social role), and from 国民 (guó mín), which refers to the people of a nation as a collective (e.g., 'national economy'). Use 公民 when talking about legal status, rights, and obligations.