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
• premiss
• 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

The theory is that Favre took a dive so that New York Giants defensive end Michael Strahan could sack him and break Gastineau’s record. —Michael McCann, Sportico.com, 15 Aug. 2025

Although Swift hasn’t publicly addressed the theories, fans have pointed out a few other reasons Oct. 3 might be significant. —Emily Blackwood, People.com, 14 Aug. 2025

Still, that hasn’t stopped fans from spreading the theory online, particularly in the wake of Swift being momentarily subpoenaed by Baldoni’s legal team. —Jami Ganz, New York Daily News, 14 Aug. 2025

Keep reading to dive into the infamous true crime case, including what investigators believe happened, the theories surrounding the murders and the latest developments in DNA technology that could help solve them. —Monica Mercuri, Forbes.com, 4 Aug. 2025