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

This suggests the approach is not just a theory but something that could work in real devices. —Rupendra Brahambhatt, Interesting Engineering, 26 Apr. 2026

The Catholic theory of the case goes like this. —Elias Wachtel, The Atlantic, 25 Apr. 2026

Their discovery supports the theory, suggested by researcher Stijn van den Hoven in 2019, that a second entrance might exist at that location. —Anne Doran, ARTnews.com, 24 Apr. 2026

The 44% theory Steve Dittmore admits that his research interest, the relationship of athletics and enrollment at small colleges, falls pretty far outside of the mainstream, even in the already-niche world of sports and higher ed. —Mark Dent, thehustle.co, 24 Apr. 2026