population density

A measure of the number of people per given unit of land.

arithmetic population density

The population of a country or region expressed as an average per unit of area. The figure is derived by dividing the population of the areal unit by the number of square kilometers or miles that make up the area.

physiological population density

The number of people per unit of arable land.

population distribution

Description of locations on the Earth's surface where populations live.

dot map

Maps where one dot represents a certain number of a phenomenon, such as a population.

megalopolis

Term used to designate large coalescing supercities that are forming in diverse parts of the world; formerly used specifically with an uppercase "M" to refer to the Boston-Washington multimetropolitan corridor on the northeastern seaboard of the United States, but now used generically with a lower-case "m" as a synonym for conurbation.

census

A periodic and official count of a country's population.

doubling time

The time required for a population to double in size.

population explosion

The rapid growth of the world's human population during the past century, attended by the ever-shorter doubling times and accelerating rates of increase.

natural (rate of) increase

Population growth measured as the excess of live births over deaths. This does not reflect either emigrant or immigrant movements.

crude birth rate

The number of live births yearly per thousand people in a population.

crude death rate

The number of deaths yearly per thousand people in a population.

demographic transition

Multistage model, based on Western Europe's experience, of changes in population growth exhibited by countries undergoing industrialization. High birth rates and death rates are followed by plunging death rates, producing a huge net population gain; this is followed by a convergence of birth rates and death rates at a low overall level.

stationary population level

The level at which a national population ceases to grow.

population composition

Structure of a population in terms of age, sex and other properties such as marital status and education.

population pyramids

Visual representations of the age and sex composition of a population whereby the percentage of each age group (generally five-year increments) is represented by a horizontal bar the length of which represents its relationship to the total population. The males in each age group are represented to the left of the center line of each horizontal bar; the females in each group are represented to the right of the center line.

infant mortality rate

A figure that describes the number of babies that die within the first year of their lives in a given population.

child mortality rate

A figure that describes the number of children that die between the first and fifth years of their lives in a given population.

life expectancy

A figure indication how long, on average, a person may be expected to live. Normally expressed in the context of a particular state.

AIDS (Aquired Immune Deficiency Syndrome)

Immune system disease caused by the Human Immunodefieciency Virus (HIV) which over a period of years weakens the capacity of the immune system to fight off infection so that weight loss and weakness set in and other afflictions such as cancer or pneumonia may hasten a person's demise.

chronic (degenerative) diseases

Generally long-lasting afflictions now more common because of higher life expectancies.

expansive population policies

Govenrment policies that encourage large families and raise the rate of population growth.

eugenic population policies

Government policies designed to favor one racial sector over others.

restrictive population policies

Government policies designed to reduce the rate of natural increase.