English Reference
noun

hypothesis

n.
US /haɪˈpɑθəsəs/ UK /haɪpˈɒθəsˌɪs/ hy·poth·e·sis

  1. 01 B2 Upper Intermediate Academic Science

    an idea that explains how something works, which scientists test with experiments to see if it is correct.

    a tentative conjecture explaining an observation or scientific problem that can be tested through investigation or experimentation.

    Simple

    The researchers developed a hypothesis to explain why the plants were dying.

    In context

    The team formulated a hypothesis regarding the chemical composition of the soil, which they then tested through a series of controlled laboratory experiments.

    Usage

    Often used with the verbs 'formulate', 'test', 'confirm', or 'reject'.

  2. 02 C1 Advanced AcademicFormal

    something that you assume is true so that you can start a discussion or an investigation.

    a premise or assumption taken to be true for the purpose of argument or investigation.

    Simple

    Let us work on the hypothesis that the economy will improve next year.

    In context

    The entire legal argument was built upon the hypothesis that the defendant had no prior knowledge of the contract's specific clauses.

    Teacher's tip

    In everyday conversation, people often use 'theory' where 'hypothesis' would be more technically accurate.

    assumptionsuppositionpremise
  3. 03 C2 Proficiency TechnicalAcademic Math

    the first part of a logical statement, often starting with the word 'if'.

    the antecedent of a conditional statement; the 'if' clause in a logical implication.

    Simple

    In the sentence 'If it rains, the ground gets wet', the hypothesis is 'it rains'.

    In context

    The mathematician demonstrated that if the initial hypothesis is false, the resulting theorem cannot be applied to this specific set of integers.

    antecedentpremise

Usage alternative hypothesis · confirm hypothesis · develop hypothesis

The UNICAMP team tested a hypothesis explaining this difference: model size.

Phys.org· 18 Aug 2026

But we need more evidence to test this hypothesis," concluded Gaetano.

ScienceDaily· 13 Aug 2026

Recorded since 1596, from Middle French hypothese, from Late Latin hypothesis, from Ancient Greek ὑπόθεσις (hupóthesis, “base, basis of an argument, supposition”, literally “a placing under”), itself from ὑποτίθημι (hupotíthēmi, “I set before, suggest”), from ὑπό (hupó, “below”) + τίθημι (títhēmi, “I put, place”). Compare hypothec.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Ancient Greek ὑπόθεσις
Level B2 · Upper Intermediate
Frequency Frequent
Updated