theoretical
Americanadjective
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of, relating to, or consisting in theory; not practical (distinguished from applied).
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existing only in theory; hypothetical.
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given to, forming, or dealing with theories; speculative.
adjective
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of or based on theory
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lacking practical application or actual existence; hypothetical
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using or dealing in theory; impractical
Other Word Forms
Etymology
Origin of theoretical
First recorded in 1610–20; theoretic, from Late Latin theōrēticus, from Greek theōrētikós, equivalent to theōrēt(ós) “to be seen” (verbal adjective derived from theōreîn “to view”) + -ikos -ic; see -al 1
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Explanation
Something theoretical is concerned with theories and hypotheses — it's not necessarily based on real life or meant to be applied to real life. Theoretical things are based on theory and ideas, while practical ones are based on practice. Theoretical thinking can be really helpful when you're trying to imagine something or problem-solve, but your theories should always be tested out in the practical world. As philosopher Bertrand Russell said, “The theoretical understanding of the world, which is the aim of philosophy, is not a matter of great practical importance to animals, or to savages, or even to most civilized men.”
Vocabulary lists containing theoretical
Albert Einstein
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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 problem is that the term premium is a theoretical construct, not something we can easily observe.
From The Wall Street Journal ● Sep. 20, 2026
Major AI companies have been racing to develop better systems, including creating what they call super intelligence - theoretical tech which is smarter than humans.
From BBC ● Sep. 19, 2026
To make sense of this theoretical point, it’s important to distinguish between stocks’ return while interest rates are rising, and their expected future returns.
From MarketWatch ● Sep. 18, 2026
Tapia Takaki has helped pioneer this experimental approach and has contributed to theoretical models in which gluons gather into localized areas of especially high density, sometimes referred to as "hot spots."
From Science Daily ● Sep. 12, 2026
But Ptolemy and his followers had assumed that measurements could be regarded as approximations: in practice, there were bound to be minor discrepancies between theoretical predictions and actual measurements.
From "The Invention of Science" by David Wootton
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
