theory

[thee-uh-ree, theer-ee] / ˈθi ə ri, ˈθɪər i /

NOUN

hypothesis, belief

Synonyms

STRONGEST

approach argument assumption code concept doctrine idea ideology method philosophy plan position premise proposal provision rationale scheme speculation suspicion system thesis understanding

STRONG

base basis codification conditions conjecture dogma feeling foundation grounds guess guesswork hunch impression outlook postulate presentiment presumption shot stab supposal supposition surmise theorem

WEAK

formularization suppose systemization

Antonyms

STRONGEST

disbelief fact information reality truth

STRONG

calculation knowledge measurement proof

WEAK

certainty

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Chemists have achieved what many once considered impossible by stabilizing an extremely reactive molecule in water, confirming a 67-year-old theory about vitamin B1.

From Science Daily • Apr. 11, 2026

One theory is that the Iranians may view Vance as a more likely partner for diplomacy given his widely reported opposition to the war, and general doubts about US interventionism.

From Barron's • Apr. 10, 2026

State wildlife officials have finally come up with a theory to explain where a giant, highly destructive rodent that’s been terrorizing California came from: Oregon.

From Los Angeles Times • Apr. 10, 2026

In theory, constant access and transparency to portfolios should make investors more informed.

From MarketWatch • Apr. 7, 2026

With the Brown decision, Colored people obtained a much-needed boost in our long fight for an equal education—in theory at least.

From "Reaching for the Moon" by Katherine Johnson

Vocabulary lists containing theory

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