決定|けっていkettei[0]heiban (flat)

1. noun, suru verb, transitive verb, intransitive verbdecision; determination
   われわれは最終的さいしゅうてき決定けっていを行おこなった。↗

   We've made a final decision.

• Synonym決めるきめるNeutralThe everyday verb for deciding or choosing, as in 「日程を決める」; 「決定」 is mostly a noun and leans formal, so plain 'to decide' takes 「決める」.
• Synonym決するけっするWrittenWritten, literary word for deciding, as in 「意を決する」; it can also mean a levee breaching. Too stiff for everyday speech.
• Synonym確定かくていWrittenWritten word for something fixed and no longer changing, as in 「当選確定」; it stresses finality, unlike a decision still in the making.
• Synonym決断けつだんNeutralA decision made boldly and without hesitation, as in 「決断を下す」; it stresses decisiveness, a nuance 「決定」 lacks.
• Synonym判断はんだんNeutralJudging after weighing things up, as in 「判断を誤る」; it centers on the thinking process, while 「決定」 is the decision made.
• Related決意けついWrittenWritten word for a firm resolve to act, as in 「決意を表明する」; it stresses one's will rather than the decision reached.
• Related決心けっしんNeutralMaking up one's own mind, as in 「決心がつく」; it centers on inner resolve, while 「決定」 is the decision itself.
• Related結論けつろんNeutralThe conclusion reached after discussion or thought, as in 「結論を出す」; 「決定」 is the decision itself, not the end point of an argument.
• Related解決かいけつNeutralSolving or settling a problem, as in 「問題を解決する」; it is about bringing a matter to a close, not making a decision.
• Related判定はんていWrittenWritten word for judging an outcome — win or lose, right or wrong — as in 「判定勝ち」; a ruling on facts, not a general decision.
• Related決議けつぎFormalFormal term for a resolution adopted by a meeting or vote, as in 「決議案」; use it for assemblies and bodies, not personal choices.
• Related規定きていWrittenWritten word for rules or provisions laid down in advance, as in 「規定に従う」; a standing rule, not a one-off decision.
• Related指定していNeutralDesignating one specific thing from many, as in 「指定席」; it is about naming or assigning, not deciding an issue.
• Related決着けっちゃくNeutralA matter being settled or brought to a close, as in 「決着がつく」; it names the final outcome, not the act of deciding.
• Related確立かくりつWrittenWritten word for firmly establishing a system, policy or position, as in 「地位を確立する」; about building up, not deciding.
• Related裁決さいけつFormalFormal term for an official ruling by an administrative authority; largely legal usage, far narrower than 「決定」.
• Related取り決めるとりきめるNeutralFor two or more parties to agree on terms, as in 「条件を取り決める」; a mutual arrangement, not a one-sided decision.
• Related落着らくちゃくWrittenWritten word for a matter or case being settled, as in 「一件落着」; the closing of an affair, not the decision itself.
• Antonym未定みていNeutralThe opposite of 「決定」: nothing has been decided yet, as in 「日程は未定」.

For a formal decision, 「決定」 is the default; for the verb, say 「決める」. Use 「決心」 or 「決意」 for making up one's mind, 「結論」 for a conclusion, 「決議」 for a formal vote, 「確定」 for something settled as final, and 「決断」 for a decisive call; 「未定」 means not yet decided. The rest cover specific fields: rulings (「判定」, 「裁決」), rules (「規定」), settlements (「解決」, 「決着」, 「落着」), agreements (「取り決める」), designations (「指定」), established systems (「確立」), and the literary 「決する」.

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

1. はっきりと決きめること。また、はっきりと決きまること。
2. 裁判所さいばんしょが行おこなう判断はんだんのうち、判決はんけつと異ことなり手続的てつづきてきな裁定さいていに関かかわるもの。裁判さいばんの一種いっしゅ。
3. 行政不服審査法ぎょうせいふふくしんさほうで、異議いぎ申立もうしたてについて成なされる判断はんだん。
4. 胚はい発生はっせいにおいて、細胞さいぼう集団しゅうだんが特定とくていの器官きかんや組織そしきなどに分化ぶんかするよう方向ほうこうづけられ、その分化ぶんかが周囲しゅういの条件じょうけんに影響えいきょうされないこと。