Define nation-state and city state, which one applies to your civilization? Then define kingdom and empire.

nation-state: a political entity (a state) associated with a particular entity (a nation).
city-state:a state consisting of a sovereign city.
a city-state would apply more to my civilization.
kingdom- a country, state, or territory ruled by a king or queen.
empire- An exclusive group of states or countries under a single supreme authority, formerly especially an emperor or empress.