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.

This will, in theory, spectacularly reduce process complexity and cost compared to their redundancy-heavy rivals.

From BBC • Apr. 13, 2026

And that’s what’s called positive-sum theory, which is that as other groups gain, my group gains, right?

From Slate • Apr. 13, 2026

An LLM is trained on the sum of human written knowledge: philosophy, history, science, political theory.

From The Wall Street Journal • Apr. 13, 2026

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

They were scientists, and their story should be grounded in theory, not guesses.

From "Mountain of Fire" by Rebecca E. F. Barone

Vocabulary lists containing theory

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The SAT: Language of the Test, List 6

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