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