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