census

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An official, usually periodic enumeration of a population, often including the collection of related demographic information.
• noun In ancient Rome, a count of the citizens and an evaluation of their property for taxation purposes.
• transitive verb To include in a census; conduct a census of.

from The Century Dictionary.

• noun In topical geom., a number referring to a geometrical figure and formed by subtracting the sum of the cyclosis and apeiry of the figure from the sum of the choresis and periphraxis.
• noun In Roman antiquity:
• noun A registered statement of the particulars of a citizen's property for the purposes of taxation.
• noun An enumeration and register of the Roman citizens in their appropriate classes, with reference to tribe, family, children, slaves, freedmen, etc.
• noun The drawing up of such a register. See censor
• noun In modern times, an official enumeration of the inhabitants of a state or country, with details of sex and age, family, occupation, possessions, etc.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot. Antiq.) A numbering of the people, and valuation of their estate, for the purpose of imposing taxes, etc.; -- usually made once in five years.
• noun An official registration of the number of the people, the value of their estates, and other general statistics of a country.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun 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 collect a census.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb conduct a census
• noun a periodic count of the population