theoretical
Americanadjective
-
of, relating to, or consisting in theory; not practical (distinguished from applied).
-
existing only in theory; hypothetical.
-
given to, forming, or dealing with theories; speculative.
adjective
-
of or based on theory
-
lacking practical application or actual existence; hypothetical
-
using or dealing in theory; impractical
Other Word Forms
Derived 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
Compare meaning
How does theoretical compare to similar and commonly confused words? Explore the most common comparisons:
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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Unit 2: Pivotal Words and Phrases
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Unit 2: Pivotal Words and Phrases
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
Rezzolla, Professor of Theoretical Astrophysics at Goethe University, emphasizes that exploring alternatives does not mean rejecting black holes.
From Science Daily • Jun. 14, 2026
Theoretical proof for this comes from a famous article written 40 years ago by William Sharpe, the 1990 Nobel laureate in economics.
From MarketWatch • Jun. 2, 2026
Theoretical physicists have pointed out fatal flaws in Mr. White’s reasoning and researchers at the Dresden University of Technology failed to replicate some of his results.
From The Wall Street Journal • Mar. 20, 2026
Theoretical modeling and interpretation were contributed by Shizeng Lin, Varsha Subramanyan, and Avadh Saxena at LANL.
From Science Daily • Dec. 2, 2025
Theoretical breakthrough that it was, complementarity did nothing to resolve the paradoxical results emanating from the atomic nucleus.
From "Big Science" by Michael Hiltzik
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.
