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