Matching Pairs Measuring populationsOnline version Now you have to relate the terms with its definition. by Laura Jiménez Ruiz 1 Population density 2 Natural increase 3 Actual increase 4 Emigrant 5 Absolute population 6 Immigrant The total number of people living in an area. A person who moves away from an area. The average number of people who live in each square kilometre of land. Includes the natural increase, the immigrants arriving and emigrants leaving. The difference between the number of births and the number of deaths. A person who moves into an area.