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

The shareable nuggets, the bling and opulence, plus the stunt casting of his reality show muse all suggest there’s something to that theory. —Lisa Respers France, CNN Money, 5 Nov. 2025

Two years earlier, however, the Los Angeles Times posed a different theory, stating that the hat was last seen with her personal secretary, Mary Gallagher. —Nicole Briese, PEOPLE, 4 Nov. 2025

Long-time political writer Andrew Sullivan wrote earlier this year that this theory has support stretching back to the 1970s and the impeachment and resignation of Richard Nixon (in whose White House Cheney served, early in his career, along with several other Bush cabinet members). —Calvin Woodward, Fortune, 4 Nov. 2025

Complementing this are quantitative market value models, which translate academic theory into operational systems already deployed in data-rich industries, and in turn help businesses unlock different and more tailored monetization strategies for their content. —Matthew Kayser, USA Today, 4 Nov. 2025