underlie
Americanverb (used with object)
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underlies,
present (3rd person singular)
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underlay,
past
-
underlain,
past participle
-
underlying
present participle
-
to lie under or beneath; be situated under.
-
to be at the basis of; form the foundation of.
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Grammar. to function as the root morpheme or original or basic form of (a derived form).
The form “boy” underlies “boyish.”
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Finance. to be primary to another right or security.
verb
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to lie or be placed under or beneath
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to be the foundation, cause, or basis of
careful planning underlies all our decisions
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finance to take priority over (another claim, liability, mortgage, etc)
a first mortgage underlies a second
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to be the root or stem from which (a word) is derived
"happy" underlies "happiest"
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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underliesimple
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underliessimple
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have underlainperfect
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has underlainperfect
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am underlyingprogressive
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are underlyingprogressive
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is underlyingprogressive
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have been underlyingperfect progressive
-
has been underlyingperfect progressive
Past
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underlaysimple
-
had underlainperfect
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was underlyingprogressive
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were underlyingprogressive
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had been underlyingperfect progressive
Future
Etymology
Origin of underlie
before 900; Middle English underlyen (v.), Old English underlicgan. See under-, lie 2
Explanation
While it’s true that when something underlies something else, it is beneath it, this does not necessarily mean subservience — it can also indicate a strong foundation or bedrock that underlies, or supports, an idea or decision. The Old English word underlicgan meant to serve or submit to another, and that meaning does carry through to the modern word underlie — to a point. Although still referring to something under something else, around 1850 the meaning of the verb shifted to include something that makes a foundation for something else. For example, one factor that underlies a patient's unusual symptoms might be his recent trip to a foreign country, where he could have picked up a local infection.
Vocabulary lists containing underlie
The Thing About Jellyfish
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"The Hand of Fatima" and "Old Ways, New World"
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Florida's B.E.S.T. Common Prefixes: under-
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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.
See Examples For:
The U.S. and China have taken different approaches in the AI models that underlie chatbots such as Claude and ChatGPT.
From The Wall Street Journal ● Jul. 17, 2026
In sum, a hard math problem in the 19th century propelled the conceptual breakthroughs that underlie all the location services on our phones today.
From Slate ● Jun. 22, 2026
"A similar mechanism could underlie individual differences in responses to other rewarding stimuli," says author and neuroscientist Josep Marco-Pallarés of the University of Barcelona.
From Science Daily ● Jan. 12, 2026
Talk to some folks in your family whom you trust to make sure you’re not overstepping any unspoken boundaries that underlie family relationships.
From MarketWatch ● Dec. 15, 2025
In particular, we know the basic laws that underlie all of chemistry and biology.
From "A Brief History of Time: And Other Essays" by Stephen Hawking
It also required him understanding that what underlies the struggles between millennials and their parents is how shockingly alike they are despite being constantly annoyed by each other.
From Los Angeles Times ● Sep. 1, 2026
This question underlies Naomi Kanakia’s snappily titled “What’s So Great About the Great Books?” a compelling if excessively cautious defense of classic literature.
From The Wall Street Journal ● Jul. 19, 2026
But five days after that, the DOJ notified the court in the Texas case that “the government has decided to maintain the definition” that underlies the ghost gun rule.
From Salon ● Jun. 2, 2026
"And that motive likely underlies this launch as well," he added.
From Barron's ● Mar. 14, 2026
Indeed, it has been an outstandingly successful theory and underlies nearly all of modern science and technology.
From "A Brief History of Time: And Other Essays" by Stephen Hawking
In postproduction, Del Toro sometimes underlay Elordi’s screams with his own guttural noises or the roars of lions and gorillas, imagining a voice created by mismatched lungs and a throat from different people.
From The Wall Street Journal ● Sep. 30, 2025
However, Sidony says her flooring was never inspected, and has shown the BBC her end of tenancy agreement which instructed her to remove carpets, underlay, gripper rods and laminate flooring.
From BBC ● Nov. 27, 2024
The turf was intended to function as an underlay for a plastic liner atop it as part of a construction project.
From Seattle Times ● Nov. 22, 2023
When his music was combined with Lynch’s “Blue Velvet,” audiences got to experience a gorgeous melody atop a disturbing, abstract underlay.
From Los Angeles Times ● Dec. 12, 2022
He stood on the edge of the sandrock shelf that underlay Laguna and looked east across the river before dawn.
From "Ceremony:" by Leslie Marmon Silko
A fundamental tension has always underlain the history of the Civil Rights movement, much as it did contemporaneous news coverage.
From The Wall Street Journal ● May 3, 2026
The slope is steep and underlain by weak, heavily fractured bedrock, making it prone to failure.
From Science Daily ● Dec. 21, 2025
The drill site in northwest Greenland was 138 miles from the coast and underlain by 4,560 feet of ice.
From Salon ● Jul. 23, 2023
The region is underlain by quartz veins, rich in ore.
From Seattle Times ● May 22, 2023
The rule of the high chiefs and notables seems to have always underlain and perhaps alternated with monarchy.
From The Works of Robert Louis Stevenson - Swanston Edition Vol. 18 (of 25) by Robert Louis Stevenson
Zanvastro is the first and only approved disease-modifying treatment for the condition, meaning it targets an underlying biological process responsible for the disease rather than simply relieving its effects.
From Science Daily ● Oct. 13, 2026
That was the case with hydraulic mining in the West, which involved aiming a torrent of water under high pressure to blast away soil and boulders to expose the underlying gold veins.
From Los Angeles Times ● Oct. 13, 2026
The brokerage says the sector’s underlying resilience remains intact, but investors will be watching whether shares hold near their technical support levels.
From The Wall Street Journal ● Oct. 12, 2026
“Our measures for underlying economic growth have not turned decisively bearish yet, but that’s market pricing collectively suggesting that maybe at least at the margin growth is softening somewhat,” Rizzuto said.
From MarketWatch ● Oct. 11, 2026
There is some truth to so-called fundamental analysis, which looks to the economic factors underlying a stock’s value.
From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos
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.
