Acitizen is best defined as a person who

lives as a permanent resident in a country
was born in a country
is native or naturalized to a country
travels every part of a country

I would say "is native or naturalized to a country."

Hey There!

There are two answers.

1. A citizen is best defined as a person who was born in a country.

2.A citizen is best defined as a person who is native or naturalized to a country.