n. The act or process of populating or peopling: as, the rapid population of the country still continues.n. The whole number of people or inhabitants in a country, county, city, or other locality: as, the population has increased 20,000 in four years; also, a part of the inhabitants in any way distinguished from the rest: as, the German population of New York.n. The state of a locality with regard to the number of its inhabitants; populousness.n. In biometry, a species, race, variety, or group of organisms that can be differentiated from other groups.