theory

noun

Words like theory

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hypothesis

Synonymnoun

possibility

Synonymnoun

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MEANING & USAGE

Definitions & examples

01noun

a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena

“theories can incorporate facts and laws and tested hypotheses”

“true in fact and theory”

02noun

a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena

“a scientific hypothesis that survives experimental testing becomes a scientific theory”

“he proposed a fresh theory of alkalis that later was accepted in chemical practices”

03noun

a belief that can guide behavior

“the architect has a theory that more is less”

“they killed him on the theory that dead men tell no tales”

Meanings and examples from Open English WordNet 2025. About our sources ↗

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Expressions with “theory”

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in theory set theory Bohr theory cell theory game theory germ theory wave theory field theory