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