Skewed sex ratio
An uneven number of males and females in a population.
Immigration
Moving into a new country to live permanently.
Net migration
The difference between the number of immigrants and emigrants in a country.
Maternal mortality rate
The number of women who die from pregnancy or childbirth per 100,000 live births.
Degenerative disease
A disease that causes gradual damage to organs or tissues over time.
Transnational migration
Movement of people across national borders while maintaining ties to both countries.
Internal migration
Moving from one place to another within the same country.
Infectious disease
A disease caused by germs that can spread from one person to another.
Interregional migration
Moving from one region of a country to another (e.g., east to west).
Rural-to-urban migration
Moving from the countryside to a city.
Arable land
Land suitable for growing crops.
Population composition
The makeup of a population by age, sex, or other characteristics.
Replacement rate
The fertility rate needed to keep a population stable (about 2.1 children per woman).
Aging population
A population with a large and growing number of elderly people.
Immigration policy
Government rules that control who can enter and live in a country.
Internally displaced person
Someone forced to leave their home but who stays within their country.
Interaregional migration (same as interregional migration)
Movement between different regions of a country.
Step migration
Migration that happens in stages (for example, village → town → city).
Emigration
Leaving one’s own country to live in another.
Pandemic
A disease outbreak that spreads across many countries or continents.
Ravenstein’s Law of Migration
Theories stating most migrants move short distances and that migration often happens in steps.
Intervening opportunity
A closer or better option that reduces the need to move farther away.
