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

And so, at first light, when firefighters had won the day and the smoke cleared to reveal the ostrich flock still standing, the sight didn’t lead to any reconsideration of the night’s theories of clandestine slaughter. — J. B. MacKinnon, Harpers Magazine, 22 Sep. 2026

The grand jury didn't find any evidence suggesting a crime occurred, or that Wells' death was motivated by race, and also took direct aim at the theories circulating on social media about the people on the boats. — Adam Sabes, FOXNews.com, 22 Sep. 2026

Grice’s implicature theory The conversational maxims proposed by Grice may be understood as common practices by means of which speakers and hearers rationally cooperate and thereby efficiently communicate with each other. — Encyclopedia Britannica, 22 Sep. 2026

The theory began after users noticed the account was commenting on posts involving Kravitz and Styles, including one showing PDA between the couple. — Alicia Urrea, Billboard, 22 Sep. 2026