Define 'GDP' and its significance in geography.

GDP, or Gross Domestic Product, measures the total value of goods and services produced within a country's borders; it's a key indicator of economic health.

Define 'megacity'.

A megacity is a very large city, typically with a population of more than 10 million people.

Define 'quaternary economic activity'.

Quaternary economic activity involves information processing and management.

Define 'spatial association'.

Spatial association is the degree to which two or more phenomena share similar distributions.

Define 'agglomeration economies'.

Agglomeration economies are benefits that firms obtain by locating near each other, typically found in cities.

Define 'rank-size rule'.

The rank-size rule is a pattern of settlements in a country such that the nth largest settlement is 1/n the population of the largest settlement.

Define 'balkanization'.

Balkanization refers to the process of fragmentation or division of a region or state into smaller regions or states that are often hostile or uncooperative with each other.

Define ' sustainability'.

Sustainability is the use of Earth's resources in a way that ensures their availability for future generations.

Define 'urbanization'.

Urbanization is the increasing number of people that live in urban areas.

Define 'cultural hearth'.

A cultural hearth is an area where new ideas and innovations spring up and spread to other parts of the world.

Define 'site' and 'situation' in urban geography.

'Site' is the physical characteristics of a place, while 'situation' refers to its location relative to other places.

Define 'cultural convergence'.

Cultural convergence is the theory that two cultures will be more and more like each other as their interactions increase.

Define 'primary economic activity'.

Primary economic activity involves the extraction of natural resources directly from the Earth.

Define 'sovereignty'.

Sovereignty is the authority of a state to govern itself or another state.

Define 'gross national income (GNI)'.

Gross National Income (GNI) measures the total domestic and foreign output claimed by residents of a country.

Define 'heartland theory'.

Heartland theory is a geopolitical concept which analyzes the political and economic success of the world's regions by geography.

Define 'globalization' in economic geography.

Globalization is the process by which businesses or other organizations develop international influence or start operating on an international scale.

Define 'physiological density'.

Physiological density is the number of people per unit area of arable land.

Define 'food desert'.

A food desert is an area that has limited access to affordable and nutritious food.

Define 'gentrification'.

Gentrification is the process of renovating and improving a house or district so that it conforms to middle-class taste.

Define 'carrying capacity' in environmental geography.

Carrying capacity is the maximum population size an environment can sustain indefinitely without degrading it.

Define 'absolute location'.

Absolute location is a point's exact location on Earth, typically expressed in coordinates of latitude and longitude.

Define 'nation-state'.

A nation-state is a state whose territory corresponds to that occupied by a particular ethnicity that has been transformed into a nationality.

Define 'transnational corporation'.

A transnational corporation operates in multiple countries with a centralized management in one country.

Define 'cultural landscape' in human geography.

A cultural landscape is an area fashioned from nature by a cultural group, encompassing cultural and natural resources.