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.

The base fee also protects the customer, in theory, from being overcharged.

From MarketWatch • Jun. 10, 2026

“I had to ask ChatGPT to explain block theory to me,” he says.

From Los Angeles Times • Jun. 9, 2026

To make matters worse for the planet nine theory, this is the fourth sednoid to be discovered.

From Science Daily • Jun. 9, 2026

Living a healthy life is easy in theory but hard in practice.

From The Wall Street Journal • Jun. 7, 2026

During the rest of the drive home, I described in detail my Cat Fantastic findings proving my theory, and then the printer making them sizzle up in smoke.

From "Sir Fig Newton and the Science of Persistence" by Sonja Thomas

Vocabulary lists containing theory

The Vocabulary.com Top 1000

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The SAT: Language of the Test, List 6

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The New SAT: The Language of the Test

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