city-state, a political system consisting of an independent city having sovereignty over contiguous territory and serving as a centre and leader of political, economic, and cultural life.
A city-state is a small independent region that consists primarily of a central city.
Historical city-states included Sumerian cities such as Uruk and Ur; Ancient Egyptian city-states, such as Thebes and Memphis; the Phoenician cities (such as Tyre and Sidon); the five Philistine city-states; the Berber city-states of the Garamantes; the city-states of ancient Greece (the poleis such as Athens, Sparta, ...
There grew to be over 1,000 city-states in ancient Greece, but the main poleis were Athína (Athens), Spárti (Sparta), Kórinthos (Corinth), Thíva (Thebes), Siracusa (Syracuse), Égina (Aegina), Ródos (Rhodes), Árgos, Erétria, and Elis. Each city-state ruled itself.
Key Difference: A city is a large and permanent settlement. Whereas, a state is a larger area, which is often governed by its own government, known as the State Government. A state is usually bigger in area than a city, and it often incorporates various cities, counties, regions, villages, towns, etc.