A citizen is someone who lives in a specific city, country, or kingdom. It especially refers to someone who is recognized officially as being a legal resident of that place.
* Depending on the context, this could also be translated as "inhabitant" or "official resident."
* A citizen could live in a region that is part of a larger kingdom or empire that is governed by a king, emperor, or other ruler. For example, Paul was a citizen of the Roman Empire, which consisted of many different provinces; Paul lived in one of those provinces.
* In a figurative sense, believers in Jesus are called "citizens" of heaven in the sense that they will live there some day. Like a citizen of a country, Christians belong to God's kingdom.