部分|ぶぶんbubun[1]atamadaka (head-high)

1. nounportion; section; part
   オレの醜みにくい部分ぶぶんがオレを引き裂ひきさく。↗

   The ugly side of myself tears me up.

• Synonym一部いちぶNeutralRefers to one part of the whole, as in 「一部の人」 or 「一部変更」; can also mean one copy or a complete set of a book.
• Synonym一部分いちぶぶんNeutralEmphasizes a small portion of the whole, as in 「ほんの一部分」; highlights the smallness of the amount more than 「部分」 does.
• SynonymパーツNeutralLoanword for machine parts or parts of the body, as in 「顔のパーツ」; 「部分」 is not limited to physical objects.
• SynonymパートNeutralThe part one is assigned in a piece of music or a work, as in 「ソプラノのパート」; also very commonly means part-time work.
• SynonymセクションNeutralA divided-off block, chapter, or department within an organization; leans toward structural divisions of organizations and documents.
• Synonym断片だんぺんWrittenWritten/formal: broken fragments and scattered pieces, as in 「記憶の断片」; stresses incompleteness, which 「部分」 does not imply.
• Synonym局所きょくしょWrittenWritten/formal: a limited spot, mostly in medical contexts, as in 「局所麻酔」; can also be a euphemism for the genitals.
• Synonym局部きょくぶNeutralA limited part of the whole, as in 「局部的な雨」; in medicine also an affected area or the genitals.
• Synonym部ぶNeutralMostly a department in an organization or a school club, as in 「営業部」 or 「サッカー部」; as 'part' it appears mainly in compounds like 「上部」.
• SynonymポーションNeutralCan mean a portion or allotted share, but is most often the single-serving amount in food service, as in 「ポーションタイプ」; for parts in general say 「部分」.
• SynonymセグメントWrittenWritten/formal loanword for segments divided out of markets or data, as in 「顧客セグメント」; common in business and IT.
• Related部門ぶもんNeutralA division of an organization or a category in a competition, as in 「営業部門」 or 「新人部門」; not used for parts of an object.
• Related部品ぶひんNeutralParts that make up a machine or product, also components in software, as in 「車の部品」 or 「ソフトウェア部品」.
• Related要素ようそNeutralAn essential constituent of something, as in 「成功の要素」; focuses on what is indispensable, not on a piece carved off the whole.
• Related成分せいぶんNeutralA substance that makes up a material, as in 「薬の成分」, also a sentence constituent; leans toward chemistry and grammar.
• Related区分くぶんNeutralA divided-off range or category, as in 「年齢区分」; the emphasis is on the act of dividing and the resulting categories.
• Related一端いったんWrittenWritten/formal: one end, as in 「ロープの一端」; also one part of a matter, as in 「一端を担う」.
• RelatedポーションNeutralCan mean a portion or allotted share, but is most often the single-serving amount in food service, as in 「ポーションタイプ」; for parts in general say 「部分」.
• RelatedコンポーネントWrittenWritten/formal loanword for components of systems, software, or audio products; focuses on the constituent units, common in technical and product descriptions.
• Related構成要素こうせいようそWrittenWritten/formal: the elements that make up a whole, used when analyzing or explaining structure; stresses the composition relation more than 「部分」.
• Related構成成分こうせいせいぶんWrittenWritten/formal: the components that make up a substance or whole; leans toward chemistry and academic use — in daily speech 「成分」 is enough.
• Antonym全体ぜんたいNeutralAntonym: the whole made up of all the parts, the opposite of 「部分」, as in 「全体と部分」.
• Antonym全部ぜんぶNeutralAntonym: all of it, not one left, opposed to 「部分」 which covers only a portion; common in colloquial speech.

「部分」 is the general word for a piece divided off from a whole. Use 「一部」 for a small part of the whole, 「部品」 for machine parts, 「部門」 for divisions of an organization, and 「要素」 for indispensable constituents. Loanwords like 「パーツ」「セクション」 and 「ポーション」 cover physical parts, sections of documents or organizations, and food servings. For fragments say 「断片」; for medical or localized areas 「局所」「局部」. The antonyms 「全体」 and 「全部」 mean the whole or all of it.

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

1. 全体ぜんたいを幾いくつかに分わけたうちのひとつ。
2. 点てん。側面そくめん。事項じこう。