hypothesis

hypothesis — noun

1. a carefully reasoned idea that offers a possible explanation for a set of facts

1.nounB2
Definition

a carefully reasoned idea that offers a possible explanation for a set of facts or observations, designed to be tested through experiments or further research to determine whether it is valid

Example

Dr. Amira formed a hypothesis about the cause of the outbreak before running any tests.

collocation: form a hypothesis

The team spent two years gathering data to test their hypothesis that rising temperatures affect bird migration.

hypothesis + that-clause for proposed explanation

Common collocations
  • form a hypothesis
  • develop a hypothesis
  • test a hypothesis
  • support a hypothesis
  • reject a hypothesis
  • propose a hypothesis
  • working hypothesis
  • null hypothesis
  • alternative hypothesis
  • initial hypothesis
Synonyms
  • theory

    a broader, more established set of principles; a theory has usually survived repeated testing, whereas a hypothesis is still being examined

  • proposition

    more formal and general; can be logical rather than empirical in nature

  • thesis

    typically refers to a central argument in an academic paper or dissertation

Antonyms
  • fact

    something known to be true through evidence, not merely proposed

  • proof

    evidence that confirms a hypothesis with certainty

Grammar Patterns

hypothesis + that-clause

to form/develop/test a hypothesis

Usage Note

In academic and scientific contexts, a hypothesis is specifically a claim that can be tested through experimentation or observation — it is not simply any vague idea. The plural form is hypotheses.

Common Mistakes

My hypothesis is that it might rain tomorrow.
My hypothesis is that increased humidity leads to a higher probability of rainfall.
A hypothesis must be testable, not just a casual prediction about a specific event.

2. a speculative assumption or opinion adopted as a starting point for reasoning or

2.nounB2
Definition

a speculative assumption or opinion adopted as a starting point for reasoning or action, formed from limited or unverified information rather than confirmed facts

Example

The detective worked on the hypothesis that the theft had been an inside job.

pattern: on the hypothesis that

Rodrigo's entire business plan rested on the hypothesis that demand would grow by at least twenty percent.

collocation: rest on the hypothesis that

Common collocations
  • on the hypothesis that
  • based on the hypothesis that
  • rest on a hypothesis
  • start from a hypothesis
Synonyms
  • assumption

    something accepted as true without proof; often used in everyday reasoning

  • conjecture

    a more formal term for a guess based on incomplete information

  • speculation

    emphasizes the lack of firm evidence; can imply a higher degree of uncertainty

Antonyms

Grammar Patterns

hypothesis + that-clause

on the hypothesis that

Usage Note

This sense is weaker and more speculative than sense 1. It is commonly preceded by on (e.g., 'on the hypothesis that') to show the basis for an argument or plan. Plural form: hypotheses.

Synonym discussion

Sense: noun/1

Hypothesis refers specifically to a testable claim used as a starting point for investigation. A theory is broader and more established — it has survived repeated testing and is widely accepted, such as the theory of evolution. A thesis is the central argument of a formal paper or dissertation, often defended in writing or debate. A proposition is a general statement put forward for consideration, which may be logical, mathematical, or rhetorical. For example: A researcher might formulate a hypothesis that a specific chemical kills bacteria, test it in the lab, and if the results hold across many studies, the finding may develop into a theory about how the chemical works.

hypothesis ↗theory ↗thesis ↗proposition ↗

Common collocations

Nouns

Adverbs

Phrases

  • working hypothesis
  • null hypothesis
  • alternative hypothesis
  • hypothesis that

Prepositions