THEORY Synonyms: 35 Similar and Opposite Words

Q: How does the noun 'theory' differ from other similar words?

The words hypothesis and law are common synonyms of theory . While all three words mean "a formula derived by inference from scientific data that explains a principle operating in nature," theory implies a greater range of evidence and greater likelihood of truth. // the theory of evolution

Q: When would 'hypothesis' be a good substitute for 'theory'?

Although the words hypothesis and theory have much in common, hypothesis implies insufficient evidence to provide more than a tentative explanation. // a hypothesis explaining the extinction of the dinosaurs

Q: When might 'law' be a better fit than 'theory'?

The meanings of law and theory largely overlap; however, law implies a statement of order and relation in nature that has been found to be invariable under the same conditions. // the law of gravitation

theory

noun

ˈthē-ə-rē

Definition of theory

as in hypothesis

an idea that is the starting point for making a case or conducting an investigation set out to prove her theory that people can't really taste any difference between colas, so they buy according to the product's image

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How does the noun theory differ from other similar words?

The words hypothesis and law are common synonyms of theory. While all three words mean "a formula derived by inference from scientific data that explains a principle operating in nature," theory implies a greater range of evidence and greater likelihood of truth.

the theory of evolution

When would hypothesis be a good substitute for theory?

Although the words hypothesis and theory have much in common, hypothesis implies insufficient evidence to provide more than a tentative explanation.

a hypothesis explaining the extinction of the dinosaurs

When might law be a better fit than theory?

The meanings of law and theory largely overlap; however, law implies a statement of order and relation in nature that has been found to be invariable under the same conditions.

the law of gravitation

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of theory Astrophysicists have several theories for what dark matter could be. — Noah Haggerty, Los Angeles Times, 28 Aug. 2026 Two competing theories are frequently offered to explain why women are dramatically underrepresented in the highest leadership positions, from Congress to Fortune 500 companies. — Laura Clawson, JSTOR Daily, 28 Aug. 2026 The working theory is that a glacial collapse was the source of the debris flow that washed away buildings, cars and people with incredible speed and force, scientists told USA TODAY. — Dinah Voyles Pulver, USA Today, 27 Aug. 2026 During the trial, prosecutors reintroduced a theory that suggested Clancy faked a suicide attempt. — Althea Legaspi, Rolling Stone, 27 Aug. 2026 See All Example Sentences for theory

Recent Examples of Synonyms for theory

Noun

The elaborate decorations could support that hypothesis, officials said.

— Andrea Margolis, FOXNews.com, 24 Aug. 2026
Their hypothesis was confirmed when footage of a Ying Yang Twins performance went viral in 2025.

— Kailyn Brown, Los Angeles Times, 21 Aug. 2026

Definition of hypothesis

Noun

Shares of CrowdStrike jumped 10% after the company delivered another beat-and-raise quarter, cementing our thesis that cybersecurity has become one of the most critical investment priorities for companies in a post-Mythos world.

— Jeff Marks, CNBC, 27 Aug. 2026
Instead, the movie’s unexpected main attraction became indelible proof of its timelessly powerful thesis of acceptance.

— Alison Foreman, IndieWire, 26 Aug. 2026

Definition of thesis

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“Theory.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/theory. Accessed 2 Sep. 2026.

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