Definition of "Population" :

noun: the act of populating (causing to live in a place)

"He deplored the population of colonies with convicted criminals."

noun: (statistics) the entire aggregation of items from which samples can be drawn

"It is an estimate of the mean of the population."

noun: a group of organisms of the same species inhabiting a given area

"They hired hunters to keep down the deer population."

noun: the people who inhabit a territory or state

"The population seemed to be well fed and clothed."

noun: the number of inhabitants (either the total number or the number of a particular race or class) in a given place (country or city etc.)

"People come and go, but the population of this town has remained approximately constant for the past decade."