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

Trump and the 'unitary executive': The presidential power theory driving his 2nd term Special focus has been on the potential implications of the case for the Federal Reserve. —Devin Dwyer, ABC News, 22 May 2025

Kennedy has a long and lucrative history of promoting theories that are both unfounded (cellphones and Wi-Fi cause cancer) and dangerous (vaccines cause autism). —Adam M. Lowenstein, The Atlantic, 21 May 2025

For example, string theory assumes a certain number of extra dimensions — a number that is not predicted by the theory itself. —Paul Sutter, Space.com, 21 May 2025

But that dubious theory has been belied by recent announcements from Trump and his trade officials. —David Goldman, CNN Money, 21 May 2025