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 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.
• 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.

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