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noun

theory

CEFR B1

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

In a sentence

Six example sentences with theory, each labelled with its topic.

  • Plate tectonics became a theory only after decades of seafloor measurements made every rival explanation impossible to defend.

    Science

  • Germ theory reorganized hospital practice, turning handwashing from an eccentric habit into the plainest requirement of surgery.

    Medicine

  • The theory of natural selection predicts which moths survive a sooty decade, and the collected specimens matched it exactly.

    Environment

  • Attachment theory explains why toddlers cry when a parent leaves the room, and decades of observation support it.

    Psychology

  • The theory of comparative advantage explains why two countries both gain from trade even when one makes everything more cheaply.

    Economics

  • Information theory sets the limit on how much data a noisy channel can carry, and every modem design bows to it.

    Technology

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Found in these word lists

Found in 7 published word listsAuthoritative

Each source is a published word list that contains theory. No exam board publishes an official GRE, GMAT or SAT list; GMAT words come from GRE lists and the Academic Word List.

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