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

Hannah Arendt never developed a general theory of friendship, yet the concept, as this study shows, anchors much of her political thought. — The New Yorker, New Yorker, 2 Nov. 2026

After the game, Jerry Jones didn’t subscribe to that theory, but the show has already made some irreversible plot decisions. — Nick Harris, Fort Worth Star-Telegram, 2 Nov. 2026

Well, the experts at LG Beauty are applying the same concept of color theory to dental care. — Michelle Lee, PEOPLE, 2 Nov. 2026

What was your reaction upon learning that Victor was right about Fruitgate with his theory on Tomica and Joe? — Dalton Ross, Entertainment Weekly, 2 Nov. 2026