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

The story behind how 4/20 became the unofficial marijuana holiday remains murky, but there are a few popular theories. —Greta Cross, USA Today, 4 Apr. 2025

Economist Rohit Krishnan tested the theory on other LLMs [large language models], finding that other flagship AIs produced similar answers, with Grok, Gemini, and Claude all creating the same tariff policy from an initial prompt. —Newsweek Staff, MSNBC Newsweek, 4 Apr. 2025

The Belgian is largely still theory, even in his mid-twenties, and his next move could either be a great success or a really expensive failure. —Joshua Kloke, New York Times, 4 Apr. 2025

Now, an actor has shot down the most prevalent finale theory about her character explicitly. —Paul Tassi, Forbes, 22 Mar. 2025