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 theories pointing to extreme heating and air-conditioning and a lack of fresh air. —Felicia Faber, FOXNews.com, 16 Apr. 2025

As future data sharpens these measurements, the findings could point us in a weird new direction – perhaps even challenging Einstein’s theory of gravity itself. —Ashley Ross, The Conversation, 16 Apr. 2025

Even if someone attempted to build one of the machines depicted in these blueprints, however, researchers point out that undecidability is a feature of physical theories and cannot literally exist in real experiments. —Charlie Wood, Wired News, 6 Apr. 2025

One of Hennigan’s leading theories is that the Grimes girls’ murders have a possible link to the 1955 murders of three young brothers, John, Anton, and Robert Schuessler, according to local WGN. —Sean Neumann, People.com, 6 Apr. 2025