1. A group or band of people.
2. A companion or associate.
3. A generational group as defined in demographics, statistics, or market research: "The cohort of people aged 30 to 39 . . . were more conservative" (American Demographics).
4. 1. One of the 10 divisions of a Roman legion, consisting of 300 to 600 men.
   2. A group of soldiers.

Usage Note: In Caesar's Gallic War a cohort was a unit of soldiers. There were 6 centuries (100 men) to a cohort, 10 cohorts to a legion (therefore 6,000 men). A century, then, would correspond to a company, a cohort to a battalion, and a legion to a regiment. Because of the word's history, some critics insist that cohort should be used only to refer to a group of people and never to an individual. In recent years, however, the use of cohort to refer to an individual rather than a group has become very common and is now in fact the dominant usage. Seventy-one percent of the Usage Panel accepts the sentence The cashiered dictator and his cohorts have all written their memoirs, while only 43 percent accepts The gangster walked into the room surrounded by his cohort. · Perhaps because of its original military meaning and paramilitary associations, cohort usually has a somewhat negative connotation, and therefore critics of the President rather than his supporters might use a phrase like the President and his cohorts.