Definitions

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.

But often there is a difference between theory and practice.

From BBC • Apr. 22, 2026

Speech-act theory explains why predictions like these can become self-fulfilling prophecies.

From The Wall Street Journal • Apr. 21, 2026

I understood, in theory, the importance of a good knife.

From Salon • Apr. 21, 2026

This is not Madman Theory, but the operative word here—the word that doesn’t fit—is theory.

From Slate • Apr. 21, 2026

And while they could not stop a conspiracy theory, they would not enable one.

From "Night Owls" by A.R. Vishny

Vocabulary lists containing theory

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The SAT: Language of the Test, List 6

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