People per unit area refers to the population density, which is the measure of how many individuals are living in a specific geographic area. It is calculated by dividing the total population by the land area.
Related terms
Population distribution: This term refers to how people are spread out across a given area.
Urbanization: Urbanization is the process of an increasing proportion of people living in urban areas compared to rural areas.
Carrying capacity: Carrying capacity is the maximum number of individuals that an environment can sustainably support.