cohortas

Cohortas is the plural form used in several Romance-language contexts for the noun cohort, referring to a group of people sharing a common characteristic or experience, or to a historical military unit. The term originates from Latin cohors, cohortis, and has carried into various modern usages with related meanings.

In historical terms, a cohort was a principal unit in the Roman army. A standard cohort comprised roughly 480 men, organized into six centuries of about 80 men each. The first cohort was often larger and held prestige within a legion, and there were specialized forms such as the urban cohorts (cohortes urbanae) stationed in and around the city of Rome. Over time, the exact size and structure of cohorts varied with era and administrative needs.

In contemporary usage, cohort describes a group of people who share a defining attribute or experience and are studied or observed together. In epidemiology and social sciences, a cohort study follows a defined group over time to examine how exposures affect outcomes. In education and workforce planning, a cohort can mean a group of students or employees who begin a program or project during the same period, progressing through it as a unit. In data analysis and marketing, cohorts are used to classify users or customers by event timing, demographics, or behavior to compare patterns across groups.

Cohortas thus span historical, academic, and analytical contexts, with the core idea remaining a defined, time-linked group rather than a single static entity.