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 anti-fraud task force has a theory. —Susan Shelley, Oc Register, 23 May 2026

Plus, Pedro Pascal reacts to theories that Mando might die, and Sigourney Weaver shares her thoughts on whether her character is secretly an Imperial spy. —Emlyn Travis, Entertainment Weekly, 23 May 2026

New theories about Powell’s true identity kept surfacing during filming, but for the Evangelistas, every lead seemed to raise even more questions than answers. —Stephanie Nolasco, FOXNews.com, 23 May 2026

In contrast to the sense of injustice felt by some players, the omissions of Foden and Palmer may have seemed contentious in theory but, in reality, caused only a minor stir. —Dan Sheldon, New York Times, 23 May 2026