How to say "subdivision" in Japanese

• 小分けこわけCommon
  noun, suru verb, transitive verbChoose this only when subdivision means dividing something into small portions or units — splitting a quantity into smaller amounts. It is about portioning things out, not about analyzing a whole.
• 細分さいぶんCommon
  noun, suru verb, transitive verbThis covers subdivision as the act of dividing something into small parts, breaking a whole down into smaller units. It is the closest match to the English word in its literal sense.
• 支部しぶCommon
  no-adjectiveHere subdivision means a branch or branch office of an organization. It never refers to the act of subdividing, so it is seldom the word you want unless you mean an organizational branch.
  あの支部しぶは炭鉱たんこう労働組合ろうどうくみあいに属ぞくしている。↗

  That branch is affiliated to the miners' union.

For the act of dividing something into small parts use 細分; for portioning a quantity into small units use 「小分け」; 支部 means only an organizational branch, not the act of subdividing.

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

• 小分けこわけsubdivision
• 細分さいぶんsubdivision (into small parts)
• 支部しぶbranch
• 分課ぶんかsubdivision
• 細別さいべつsubdivision
• 細分化さいぶんかsubdivision
• 亜門あもんsubphylum
• 下位分類かいぶんるいsubclass