How to say "cohort" in Japanese

• コホート
  nounThe loanword, used especially in statistics, medicine, and data analysis for a group of subjects sharing a defined characteristic and studied as a group; it has a technical, academic feel.
• グル
  nounCovers only the informal sense: an accomplice, a partner in some scheme, often a disreputable one. It is the colloquial 'partner in crime' word, not the word for research or demographic cohorts.
  彼かれは不良ふりょう仲間なかまとぐるになっていた。↗

  He fell into bad company.
• 代だい
  noun, noun (suffix)Covers the demographic sense: a generation — people born in the same period — or a school-year group. Use it when grouping people by birth year or by the school year they belong to.
  あの会社かいしゃとの取り引とりひきは父ちちの代だいから糸いとを引ひくように切きれない。↗

  Our transactions with that firm have continued unbroken since my father's generation.

Choose 「コホート」 for the technical research sense of a studied group, 代 for a birth- or school-year group (a generation), and 「グル」 only for the colloquial 'partner in crime' sense of cohort.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• コホートcohort
• ぐるaccomplice
• 代だいgeneration