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