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

Over the decades, as Shakur’s stature grew and evolved, there were flare-ups of media interest and theories but no conclusions or arrests. — Dominic Patten, Deadline, 13 Oct. 2026

Be curious, not judgmental All of the above has unleashed theories about Simmons among fans and, of course, in the online world. — Kansas City Star, 12 Oct. 2026

Their theory is that any kind of infrastructure is used or can be used for military purposes. — Aidan Stretch, CBS News, 12 Oct. 2026

Without the United States, the theory goes, the region would settle into its own equilibrium. — Philip H. Gordon, Foreign Affairs, 12 Oct. 2026