Boundary – an invisible, vertical plane that separates one state from another, which includes both the airspace above the line on the surface and the ground below.
Centripetal force – a force that tends to bind a state together.
Centrifugal force – a force that tends to break a state apart.
Compact state – a state where the distance from the center to any border does not vary significantly; roughly circular.
Ethnic boundary – a boundary that encompasses a particular ethnic group.
Fragmented state – a state whose territory is not contiguous, but consists of isolated parts such as islands.
Geometric boundary – a boundary that follows a straight line and may coincide with a line of latitude or longitude.
Gerrymandering – the process of redrawing legislative districts in order to benefit the party in power and ensure victory in elections.
Irredentism – an effort to expand the political influence of a state on a group of people in a neighboring state.
Multi-national state – state that has more than one nation within their borders.
Nation – group of people bonded by cultural attributes such as language, ethnicity and religion.
Nation-state – state in which the territorial boundaries encompass a group of people with a shared ethnicity.
Physical boundary – a boundary that follows a natural feature on the landscape such as a river, mountain range, or lake.
State – a formal region in which the government has sovereignty or control of its own affairs within its territorial boundaries.
Stateless nation – a nation that aspires to become a nation-state but does not yet have their own territory.
Supranational organization – an alliance involving three or more states who have shared objectives that may be economic, political/military, or cultural.
Terrorism – intimidation of a population by violence in order to further political aims.