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

Social media exploded as the clock struck midnight and theories began to surface surrounding a March 27 arrival for Minaj’s sixth studio album. —Michael Saponara, Billboard, 24 Sep. 2025

However, in the early 1980s, a new theory called cosmic inflation came along, suggesting that before the hot Big Bang, the Universe behaved very differently, pushing any hypothetical singularity unobservably far back. —Ethan Siegel, Big Think, 24 Sep. 2025

Scientists have developed several theories to explain the ribbon signature. —Kyle Orland, ArsTechnica, 24 Sep. 2025

However, this is just one theory. —Caché McClay, USA Today, 24 Sep. 2025