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
- antitheoretical adjective
- nontheoretic adjective
- nontheoretical adjective
- theoretically adverb
- untheoretic adjective
- untheoretical adjective
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.
While at the University of California, Berkeley, pursuing a doctorate in theoretical physics, he started taking computer science courses out of curiosity.
From The Wall Street Journal • Apr. 16, 2026
Because of this, scientists have had to rely heavily on theoretical models rather than direct measurements.
From Science Daily • Apr. 14, 2026
“That’s no longer a theoretical thing,” Altman said.
From MarketWatch • Apr. 11, 2026
In that theoretical promised land, the objective would be to care deeply about the people and issues that are worth our attention, not about stuff that doesn’t matter.
From Salon • Apr. 5, 2026
Figure 6.11: These modes are part of the same theoretical system as the church modes, but they were not used in the middle ages.
From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones
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.
