Synonyms of theory

theory

noun

ˈthē-ə-rē 

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

Synonyms & Similar Words

• hypothesis
• thesis
• proposition
• premise
• assumption
• suggestion
• guess
• supposition
• theorem
• impression
• proposal
• inference
• hunch
• conjecture
• concept
• speculation
• generalization
• suspicion
• presumption
• notion
• presupposition
• conception
• concession
• construct
• abstraction
• surmise
• feeling
• guesswork
• proffer
• inkling

Antonyms & Near Antonyms

• fact
• knowledge
• assurance
• certainty

Synonym Chooser

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

Recent Examples of theory

That means the 2026 midterms could end up being a giant national experiment that tests the populist left’s theory of victory. — Michelle Goldberg, Mercury News, 27 June 2026

In theory, if all 11 of your active players go through, that’s an immediate 22 points before any goals, assists or clean sheets are even considered. — Abdul Rehman, New York Times, 27 June 2026

Then along came a graduate student with barely any expertise in Ramsey theory. — Leila Sloman, Quanta Magazine, 26 June 2026

And her theory is embodied by Bartlett’s leper character, who in his literal and physical anonymity feels simultaneously like a manifestation of the island itself and a guardian of its promise. — Roxana Hadadi, Vulture, 26 June 2026