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

Gray has two theories about why such bans don’t seem to be producing bigger shifts. — Joshua Rothman, New Yorker, 4 Sep. 2026

There's opinion journalism, and then there are crackpot theories that get in the way of legitimacy. — Bill Goodykoontz, AZCentral.com, 3 Sep. 2026

The theory is further bolstered by the jewelry’s material,Copper alloy was considered a cheaper metal at the time, and usually only worn by lower status individuals. — Andrew Paul, Popular Science, 3 Sep. 2026

Social media lit up with speculation that Bartiromo might be in line to become White House press secretary, though no reporting has backed up that theory. — Brian Stelter, CNN Money, 3 Sep. 2026