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 indicator’s theoretical rationale is that households are late to jump on the market’s bandwagon, and are therefore most bullish at or near tops and most bearish at or near bottoms.
From MarketWatch ● Aug. 24, 2026
Crucially, this indicator’s theoretical rationale is distinct from each of the other eight.
From MarketWatch ● Aug. 24, 2026
"From a theoretical standpoint, this is a major step forward in our understanding of the physics at play in these systems."
From Science Daily ● Aug. 23, 2026
There is a gorgeous, heartbreaking story about a piano prodigy in France during World War I. The final story concerns the marriage between a Dutch clockmaker and a theoretical physicist.
From The Wall Street Journal ● Aug. 18, 2026
Real cities have been replaced by coordinates; real places by theoretical spaces.
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.
