Definitions of demographics on the Web:

• Demographic or demographic data refers to selected population characteristics as used in government, marketing or opinion research, or the demographic profiles used in such research. Note the distinction from the term "demography" (see below. ...
  en.wikipedia.org/wiki/Demographics

• the characteristics of human populations for purposes of social studies
  en.wiktionary.org/wiki/Demographics

• : A demographic criterion: a characteristic used to classify people for statistical purposes, such as age, race, or gender; A demographic group: a collection of people sharing a value for a certain demographic criterion; : An individual person's characteristic, encoded for the purposes of ...
  en.wiktionary.org/wiki/demographic

• Recognizable characteristics of media consumers such as age, gender, education and income level.
  www.media-awareness.ca/english/resources/educational/teaching_backgrounders/media_literacy/glossary_media_literacy.cfm

• The statistical data of a population showing average age, income, education, etc.
  www.autoshopowner.com/glossary.html

• As of the census of 2000, there were 4,246 people, 1,630 households, and 1,155 families residing in the city. The population density was 2,615.3 people per square mile (1,012.0/km²). There were 1,740 housing units at an average density of 1,071.7/sq mi (414.7/km²). ...
  www.wamegopedia.com/

• demographic - referring to numerical characteristics of a population (eg population size, age structure)
  kurrawa.gbrmpa.gov.au/corp_site/info_services/publications/reef_research/issue2_99/gloss.htm

• demographic - A statistical characteristic of a human population (such as name, age, zip code or income) that is important for creating particular target-groups.
  emailmarketingpro.org/email-marketing-terms/

• Basic statistical information about a population, such as age, income, gender, etc.
  sanctuaries.noaa.gov/education/evaluation/glossary.html

• Statistical data that describes the makeup of a given user base, and includes information such as age range, gender, education levels, and average household income. Demographic data is one of the tools used to match ad space with an advertising campaign. Up
  www.adserversolutions.com/adserver/adterms.html

• Evaluation of housing requirements based on family size, ages, occupations, marital status and other population characteristics.
  www.yourwebassistant.net/glossary/d3.htm

• the study of, or information about, people's lifestyles, habits, population movements, spending, age, social grade, employment, etc., in terms of the consuming and buying public; anyone selling to the consumer sector will do better through understanding relevant demographic information.
  www.bizjobs.com/business_glossary.php

• Common characteristics used for population segmentation. Typical demographic data include age, gender, occupation, and income.
  www.mdwe.com/online_ad_terms.htm

• having to do with population statistics (for example, age, gender, religion, ethnic background, education level, profession)
  www.indianahistory.org/programming/immigration/glossary/index.html

• Demographics is data about the size and characteristics of a population or audience (for example, gender, age group, income group, purchasing ...
  developer.admob.com/wiki/Definitions