How to say "hypothesis" in Japanese

• 想定そうていCommon
  noun, suru verb, transitive verbFor 'hypothesis' as an envisaged scenario — what you suppose or expect might happen, as in planning — this is the natural choice; it is not the word for a scientific theory to be tested.
  枝えだが伸のび、実じつが成なることを想定そうていして接はぐ場所ばしょを選えらびましょう。↗

  Select the graft point after imagining how the branches will extend and fruit grow.
• 仮説かせつCommon
  nounThe word for a hypothesis in the scientific sense: a tentative theory proposed and then tested or verified, as in research or academic discussion.
  これらのデータはその仮説かせつを支持しじしている。↗

  This data supports the hypothesis.
• 仮定かていJLPT N2approx.Common
  noun, suru verb, transitive verbCovers 'hypothesis' as an assumption made for the sake of argument or planning — something you tentatively treat as true in order to reason from it.
  彼女かのじょがここにいると仮定かていしてみよう。↗

  Let's suppose that she is here.
• 前提ぜんていJLPT N1approx.Common
  nounReally 'premise' or 'prerequisite': something taken for granted as a starting point. For 'hypothesis' it works only when the hypothesis is a given, not something to be tested — seldom the word you want.
  その前提ぜんていが妥当だとうかどうかよく考かんがえるべきだ。↗

  You ought to think over whether the premise is valid or not.

Use 仮説 for a tentative theory to be tested, especially in research; 仮定 for an assumption made for the sake of argument; 想定 for a supposed scenario you anticipate; and 前提 only for a premise taken as given.

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

• 想定そうていhypothesis
• 仮説かせつhypothesis
• 仮定かていassumption
• 前提ぜんていcondition
• 比定ひていhypothesis (formed by comparison with other similar objects)
• 憶説おくせつhypothesis
• 仮言かげんhypothesis