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

Leadership theory suggests CEOs should focus on high-level issues such as strategy and resource allocation. —Scott Cook, Harvard Business Review, 14 Oct. 2025

One theory for how Whitney may have escaped his genetic fate stems from his time in the Navy. —Melissa Rudy, FOXNews.com, 14 Oct. 2025

Howitt and Aghion followed up with a theory on how creative destruction allows one technological advance to give way to another, so what's a breakthrough in one generation is obsolete by the next. —Scott Horsley, NPR, 13 Oct. 2025

Yet his theory leans on outdated models of deep history. —Manvir Singh, New Yorker, 13 Oct. 2025