Noun

census (plural censuses)

1. An official count of members of a population (not necessarily human,) usually residents or citizens in a particular region, often done at regular intervals.

Verb

to census (third-person singular simple present censuses, present participle censusing, simple past and past participle censused)

1. To collect a census.

A census is the procedure of systematically acquiring and recording information about the members of a given population. It is a regularly occurring and official count of a particular population. The term is used mostly in connection with national population and housing censuses; other common censuses include agriculture, business, and traffic. In the latter cases the elements of the 'population' are farms/businesses/etc rather than people. The United Nations defines the essential features of population and housing censuses as "individual enumeration, universality within a defined territory, simultaneity and defined periodicity", and recommends that population censuses are taken at least every 10 years. The term itself comes from Latin: during the Roman Republic the census was a list that kept track of all adult males fit for military service.

The census can be contrasted with sampling in which information is obtained only from a subset of a population, sometimes as an Intercensal estimate. Census data is commonly used for research, business marketing, and planning as well as a base for sampling surveys. In some countries, census data is used to apportion electoral representation (sometimes controversially - e.g. see Utah v. Evans).