A number of people who share a common characteristic linked to a specified place and time (e.g., born in a particular geographical location over a specified time period or the year of marriage). There are many different kinds of cohorts, examples being: the birth cohort of 1958 is comprised of all individuals born in that calendar year, while the marriage cohort of 1982 consists of all individuals married in 1982. The origin of the word derives from the Latin for a unit of the Roman Legion (i.e., a division) consisting of 300 to 600 men.
See Cohort effect, Cross-sectional design, Community, Longitudinal design, Longitudinal studies, Multiple cohort study, National Literacy Strategy, Panel studies, Period effect, Population (biology and ecology), Prospective cohort