Sovereignty: Sovereignty refers to the supreme authority of a state over its territory and people without external interference. It encompasses political independence and self-governance.
Border: A border is a physical or imaginary line separating two political entities such as countries, states, regions, etc. Borders often define territorial limits between nations.
Nation-State: A nation-state is a political entity in which a particular cultural or ethnic group shares both a common identity (nation) and a defined territory (state). Examples include Japan, France, and Iceland.