# hypothesis

/haɪˈpɑθəsəs/ (US) · /haɪpˈɒθəsˌɪs/ (UK)

Source: https://englishreference.com/word/hypothesis
Updated: 2026-06-20

## Senses

### 1. scientific theory

noun · CEFR B2 · Academic

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

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

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

noun · CEFR C1 · Academic · Formal

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

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

- Let us work on the hypothesis that the economy will improve next year.
- The entire legal argument was built upon the hypothesis that the defendant had no prior knowledge of the contract's specific clauses.

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

### 3. logic/math

noun · CEFR C2 · Technical · Academic

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

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

- In the sentence 'If it rains, the ground gets wet', the hypothesis is 'it rains'.
- The mathematician demonstrated that if the initial hypothesis is false, the resulting theorem cannot be applied to this specific set of integers.

## Examples

- The scientist created a hypothesis to explain why the plants died.
- Researchers are testing the hypothesis that a lack of sleep directly affects memory retention in young adults.
- While the initial data appeared to support the researcher's hypothesis, a more rigorous statistical analysis revealed that the observed correlation was likely a result of sampling bias rather than causation.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.