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

That’s the high concept of the rudimentary screenplay by Umair Aleem, who seems to have spent time studying Aristotle’s unity of place theory. — Frank Scheck, HollywoodReporter, 7 Oct. 2026

Researchers would be a big step closer to a unified theory of computational difficulty. — Quanta Magazine, 7 Oct. 2026

Set across 12 days, 22 players emulate the TV show at the castle by building trust with other players during missions as well as building believable theories during The Round Table. — Tanya Fedak, Variety, 6 Oct. 2026

As Berg explained, the key to the players’ theory rests on signing away their rights to the NCAA. — Michael McCann, Sportico.com, 6 Oct. 2026