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

An autonomous system equaling the best human fleets signals that automation is moving from theory to reality. —Kurt Knutsson, FOXNews.com, 29 Oct. 2025

This means that the authors only need to prevail on one of their theories. —Winston Cho, HollywoodReporter, 29 Oct. 2025

If Questlove’s theory is right that an album truly starts with its third song, this is a curious choice for the foundation of Rumours. —Alan Light, Rolling Stone, 29 Oct. 2025

Though the origin of transients is unknown, scientists have proposed several theories. —Chris Young, Interesting Engineering, 28 Oct. 2025