Definition of cohort in US English:



  • 1treated as singular or plural An ancient Roman military unit, comprising six centuries, equal to one tenth of a legion.

    • ‘They were adopted by the Romans, and under the system introduced by Marius became the characteristic standard of the legion, with different devices being used for those of cohorts and centuries.’
    • ‘Clearly Firmus is a key individual, as he has the authority to allocate grain to a detachment of legionaries in the fort; yet does this mean that he is a senior centurion of one of the cohorts, or is he just a middle-man?’
    • ‘He replaced the existing praetorian guard with sixteen cohorts recruited from his German legions.’
    • ‘Sometimes linked with Mars, he was honoured by various senior officers, by soldiers of all the legions, and by the cohort at the fort of Birdoswald.’
    • ‘Initially designed for cavalry, the fort was garrisoned by an infantry cohort of 800 men in the C2.’
    • ‘The cohorts, divided into six centuries (100 men in each century) commanded by a centurion, became the main tactical unit of the army.’
    • ‘A legion varied in strength from four-thousand to six-thousand men, and was subdivided onto ten cohorts.’
    unit, outfit, force
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  • 2treated as singular or plural A group of people banded together or treated as a group.

    ‘a cohort of civil servants patiently drafting legislation’
    • ‘Modern warfare, modern weaponry is so hi-tech that if you try to run our defences on the basis of conscription, you have your professional soldiery permanently employed training successive cohorts of conscripts.’
    • ‘The researchers studied the reported mortality rates and causes of death in a cohort of women who used homeless shelters in Toronto.’
    • ‘To begin, I will discuss two central notions - the issue of nationalism and the issue of women as a political cohort - from a deconstructionist perspective.’
    • ‘This October its first undergraduate cohort launches a new BA in geography & archaeology.’
    • ‘As a result, the Army will soon have a cohort of company grade officers who are accustomed to operating independently, taking the initiative, and adapting to changes.’
    • ‘Exactly how China's future cohorts of young men are to be socialized with no prospect of settled family life and no tradition of honorable bachelorhood is a question that can be asked today, but not answered.’
    • ‘Laslett was part of a remarkable cohort of undergraduate historians at St John's College, Cambridge in the late 1930s which included the likes of John Habbakuk and Edward Miller.’
    • ‘The rollback has been gradual, first offering free doctor's visits to children, then pensioners, then subsidies to various cohorts of adults - and now, it finally seems to be bearing fruit.’
    • ‘The top schools cater for a cohort of students whose parents can afford to pay for grinds and revision courses.’
    • ‘This cohort had difficulty settling down in the more pacific atmosphere of the New Economic Policy.’
    • ‘In a cohort of experienced Swiss general practitioners most were unable to interpret correctly numerical information on the diagnostic accuracy of a screening test’
    • ‘There is no way earlier cohorts of illicit immigrants are going to be deported except through due process which may be redefined if necessary.’
    • ‘A New Zealand survey was conducted by the ministry of Research Science and Technology to examine the experiences of a cohort of graduates in the first five years after they graduated.’
    • ‘Both the Roman Catholic and the Dutch Reformed denominations were underrepresented in the cohorts; Roman Catholics more so than Dutch Reformed.’
    • ‘The distribution of occupations among the first three generations is significant per cohort and therefore not due to chance.’
    • ‘Among the primary readjustment problems for this cohort were the poor economic situation, the attitudes and gossip of locals, inefficiency, and the slow pace of life.’
    • ‘Having spent months recruiting, training, and developing a cohort of staff, directors wonder what they might do to entice staff to return.’
    • ‘A cohort of more than 900 women who delivered by cesarean section at a large Vietnamese hospital was studied over a four-month period in 1997.’
    • ‘Subjects responding may represent a cohort of individuals who are more motivated and generally more compliant with therapy than nonresponders.’
    • ‘In a cohort of 220 patients recruited from general practice, a quarter died within three months.’
    1. 2.1 A group of people with a common statistical characteristic.
      ‘the 1940–44 birth cohort of women’
      • ‘Five of the databases were established over 50 years ago, four being cancer registries and one a longitudinal birth cohort.’
      • ‘The only exception to this generalization comes from the Dublin 1899 cohort, where the percentage dropped to just slightly more than one-tenth of the membership.’
      • ‘In June 1999 Taylor et al published in the Lancet the results of a study in which they identified children diagnosed as having autism in the North East Thames region for birth cohorts from 1979 to 1992.’
      • ‘However, even though the age cohort is restricted for pension cases, and the men limited to Civil War veterans, the data may be wider and deeper than they first appear.’
      • ‘Our program seeks to build a community of learners by bringing together each year's cohort for a common course each semester.’
      • ‘Next we examined the extent and direction of attitude change for both males and females as we followed single year birth cohorts over time.’
      • ‘Of their children, taking the cohort born before 1968, however, only a third remained in unskilled work, and 54 per cent were in clerical or management posts.’
      • ‘Similarly, the association of family and school problems with early age of onset of escalated drug use was also consistent across gender and birth cohorts.’
      • ‘Indeed, nine of the eleven shop assistants in the 1899 cohort were migrants into the city.’
      • ‘Later age of onset of first drug use was significantly associated with delayed age of first treatment among all male birth cohorts and females born before 1971.’
      • ‘This flattening off persisted after allowing for expected delay in diagnosis in more recent birth cohorts.’
      • ‘For infant deaths and postneonatal deaths, deaths were attributed to the year of birth, and the 1981-1991 birth cohort was analyzed.’
      • ‘This 1997 survey group was generally more positive about their experiences at school than previous cohorts of school leavers had been.’
      • ‘The Sutton Trust, an educational charity, compared two cohorts of young men, born in 1958 and 1970 respectively.’
      • ‘The charts and data presented are very interesting, including the revelation that male modern heights and standards were achieved by the birth cohort of 1925.’
      • ‘At the national level, they show that for most of the twentieth century, each successive cohort of young people left home at an average age below that of the cohort immediately preceding them.’
      • ‘Although biomass allocation patterns were statistically significant between cohorts during juvenile growth stages, the most obvious differences were at late-fruiting.’
      • ‘Accordingly, the Census Bureau combined its samples, basing its estimates on four-year cohorts.’
      • ‘Flanagan was twenty-one years old when she joined the Central Branch of the league as part of the 1899 cohort.’
      • ‘Deaths due to malignancy were mainly linked to smoking, previously shown as common in our cohort.’
      group, grouping, category, categorization, grade, grading, classification, class, set, section, division, order, batch, list
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  • 3derogatory A supporter or companion.

    • ‘Yet far more of the portraits of Pompadour were not shown in public at all, destined instead for palatial private decors where they could be enjoyed alone by the King and his cohorts and by her own intimates.’
    • ‘For the easily confused, a cast directory helps you to identify all the various roles for the Pythons and their supporting cohorts.’
    • ‘Elaine May plays Frenchy's batty sister and Tony Darrow, Michael Rapaport and John Lovitz offer able support as Ray's cohorts.’
    • ‘Much too far by their own reckoning but not far enough in the eyes of ardent nationalists and radical land reformers like Davitt and his cohorts.’
    • ‘Although there are a few solid cohorts of these fine men who are still fighting for worker justice, by and large the generation of religious leaders that grew up during the great labor organizing expansion is dying.’
    • ‘Unlike his cohorts of the early 1980s, Keith Haring and Jean-Michel Basquiat, Kenny Scharf has yet to be given a major New York museum exhibition.’
    • ‘Graves used his influence to get one of his closest Landmark cohorts, A. C. Dayton, appointed as president of the Sunday School Union and himself selected as secretary.’
    • ‘He's a cohort of Ricci's and he worked in the Smart neighborhood.’
    • ‘AS NAT ‘KING’ COLE BEGAN his concert, Adams and his cohorts waited in the shadows for a signal to rush the stage.’
    • ‘How to understand the older generation which supported Hitler and his cohorts?’
    • ‘He and his ideological cohorts are willing to brand any and all groups they dislike as ‘terrorists,’ then use our tax dollars and military to kill them.’
    • ‘The major reform of the CAP was agreed in 2003 and supported by the British and their cohorts in the so-called club of six member states, she said.’
    • ‘Hunter felt comfortable in Norway's relaxed air and brought a few old cohorts for company.’
    • ‘Ian McGeechan and his cohorts of coaches will no doubt spend countless hours in a darkened room poring over this video-nasty; let's hope they can work the oracle before the visit to Rome in a fortnight.’
    • ‘Not wanting to be outdone by Reagan and his cohorts, Democratic Party politicians took every opportunity to promote anticommunism and militarism.’
    • ‘Goodenow and his cohorts tell the players that fans support them, but just who the heck does the NHLPA think will back their picket line when the owners turn to replacement players next winter?’
    • ‘Without precisely encouraging strife among his cohorts, Hitler was capable of remarkable neutrality - an ability to remain above the battle.’
    • ‘While both Vovelle and Furet toured colloquia in every continent, they never appeared together on the same platform, and Furet and his cohorts boycotted the biggest conference of the year organized by Vovelle in Paris.’
    supporter, follower, adherent, devotee, champion, backer, upholder, promoter, fanatic, fan, enthusiast, stalwart, zealot, disciple, votary
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The co- in cohort is not a prefix signifying a joint or auxiliary relationship (as in coauthor or codependency). The word derives from the Latin cohors, an ancient Roman military unit, and also ‘band of people with a common interest.’ In the mid 20th century, a new sense developed in the US, meaning ‘a companion or colleague,’ as in young Jack arrived with three of his cohorts. Although this use is well established, there are still some people who object to it on the grounds that cohort should be used only for groups of people, never for individuals


Late Middle English: from Old French cohorte, or from Latin cohors, cohort- ‘yard, retinue’. Compare with court.