underground

adverb
un·​der·​ground | \ ˌən-dər-ˈgrau̇nd How to pronounce underground (audio) \

Definition of underground

 (Entry 1 of 3)

1 : beneath the surface of the earth
2 : in or into hiding or secret operation

underground

noun
\ ˈən-dər-ˌgrau̇nd How to pronounce underground (audio) \

Definition of underground (Entry 2 of 3)

1 : a subterranean space or channel
2 : an underground city railway system
3a : a movement or group organized in strict secrecy among citizens especially in an occupied country for maintaining communications, popular solidarity, and concerted resistive action pending liberation
b : a clandestine conspiratorial organization set up for revolutionary or other disruptive purposes especially against a civil order
c : an unofficial, unsanctioned, or illegal but informal movement or group especially : a usually avant-garde group or movement that functions outside the establishment

underground

adjective
un·​der·​ground | \ ˈən-dər-ˌgrau̇nd How to pronounce underground (audio) \

Definition of underground (Entry 3 of 3)

1 : being, growing, operating, or situated below the surface of the ground
2 : conducted by secret means
3a : existing outside the establishment an underground literary reputation
b : existing outside the purview of tax collectors or statisticians the underground economy
4a : produced or published outside the establishment especially by the avant-garde underground movies underground newspapers
b : of or relating to the avant-garde underground an underground moviemaker an underground theater

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Examples of underground in a Sentence

Adverb

They had been living underground as fugitives.

Noun

I've ridden on the New York subway, the Paris Metro, and the London Underground. joined the underground while still a teenager

Adjective

The drugs are supplied through an underground network. She loves the city's underground music scene.
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Recent Examples on the Web: Adverb

Fifty meters underground, the air is hotter than at the surface. Vasco Cotovio, CNN, "A trail of 'bloody gold' leads to Venezuela's government," 20 Aug. 2019 Guest speaker Mike Sinacori will discuss the process for placing utilities underground in the community. Daily Pilot, "Around Town: George Thorogood, Live and Bush among headliners of upcoming Pacific Amphitheatre concerts," 8 Aug. 2019 Many people work as city guides, but this man really comes from underground. Washington Post, "Russian tour guide’s personal story is an attraction," 30 July 2019 For instance, transporting 70,000 tons of argon — which needs to stay cool in transit in order to remain in its liquid state — to South Dakota and then underground is a task never before attempted. Nathaniel Scharping, Discover Magazine, "Why Fermilab is Making A Neutrino Detector 800 Miles Long," 12 Mar. 2019 All parking would be placed underground, avoiding a repeat of the monster-sized garage bases that blight so many recently constructed residential high-rises. Blair Kamin, chicagotribune.com, "New plans for Spire site: Arresting towers, solid urban design and room for improvement," 16 May 2018 In contrast, San Diego and the electric utility that serves it — San Diego Gas & Electric Co. — have made placing lines underground a high priority. David R. Baker, San Francisco Chronicle, "Wine Country fires: PG&E often diverts money for undergrounding power lines," 12 Mar. 2018 The tubes carrying the pods could either be built above ground on columns alongside a current highway corridor or potentially placed underground. Marco Della Cava, USA TODAY, "Is Missouri ready for 700 mph hyperloop commutes?," 30 Jan. 2018 The cave, Poland’s deepest and longest, has 24 kilometers (15 miles) of passages that go 800 meters (2,625 feet) underground. Washington Post, "Rescuers use explosives to seek 2 cavers trapped in Poland," 19 Aug. 2019

Recent Examples on the Web: Noun

This neutrino trap that Indu is helping design will be placed deep underground, almost one kilometre under a hill. Nandita Jayaraj, Quartz India, "Meet Indumathi, the Indian scientist who wants to capture one of the universe’s smallest particles," 27 Aug. 2019 The sci-fi novel is the second book in a trilogy about a group of monsters who were once underground and are now taking over New York City and the world. Micah Walker, Detroit Free Press, "'Impractical Jokers' star Jim Murray touts new book as comedy tour hits Michigan," 9 Aug. 2019 The dark web is the world of the criminal underground, where data is bought and sold by criminal actors—including nation states—and used to fund nefarious activities. Kristina Libby, Popular Mechanics, "The Capital One Hack Probably Put Your Data on the Dark Web," 30 July 2019 There is a really cool underground of extremely heavy music. Bryan Reesman, Billboard, "311's Nick Hexum on Hitting the Road With Dirty Heads & Embracing Their Cult Status," 12 July 2019 Permian Basin Houston pipeline operator Kinder Morgan is preparing for a round horizontal drilling in West Texas where the company owns a handful of oil wells that are stimulated by injecting carbon dioxide underground. Sergio Chapa, Houston Chronicle, "Drilling Down: Surge Energy’s record-breaking lateral in the Permian Basin," 22 July 2019 Heck, one of the official buildplates comes with a massive underground cavern, but there's no way to reach it. Sam Machkovech, Ars Technica, "Minecraft Earth’s closed beta: This augmented reality needs more augmenting," 16 July 2019 How much later was one of the key findings: the water reemerged two weeks to eight months later, with an average time underground of 45 days. Erica Gies, National Geographic, "Seeking relief from dry spells, Peru’s capital looks to its ancient past," 9 July 2019 To require the homeless to come into shelters is just going to push them deeper underground and into hiding. Los Angeles Times, "Desperate to ease homelessness, California officials look to New York ‘right to shelter’ policy," 21 July 2019

Recent Examples on the Web: Adjective

Google plans to put parking in the area underground and focus on people, not cars, Arena said. George Avalos, The Mercury News, "Google unveils its vision for downtown San Jose transit village," 23 Aug. 2019 Muni rerouted several bus lines and advised the public to take the underground to avoid the road closure. Evan Sernoffsky, SFChronicle.com, "The Scanner: Crackdown in SF’s Tenderloin leads to scores of arrests," 12 Aug. 2019 The firm is taking 25 samples across both sites, anywhere from 2 inches to 12 inches underground, including a pair of 20-foot-deep samples where the pedestrian bridge is planned over Indiana Street. John Aguilar, The Denver Post, "Trail plans prompt first soil samples in 13 years at Rocky Flats," 2 July 2019 Los Retros just got off the road opening for Hawthorne heartthrob Cuco, a connection that further confirms the rise of a new generation of Mexican American balladeers coming up from the underground. Randall Roberts, latimes.com, "California Sounds: New music from Los Retros; a Chip and Tony Kinman retrospective," 27 June 2019 Many of these animals, as well as rodents and rabbits, could have survived by riding out the fire in underground burrows, reappearing after the fire has passed, Burnett said. Priscilla Totiyapungprasert, azcentral, "Rabbits, bears and bobcats: How has the Woodbury Fire affected Arizona wildlife habitat?," 26 June 2019 That’s what cybersecurity giant McAfee found during its investigation into underground and nefarious hacker marketplaces on the internet, commonly known as the Dark Web. Brooke Crothers, Fox News, "Access to airport security systems are being sold by hackers for as little as $10," 13 July 2018 Gettinger pointed to Austin and San Antonio as cities currently using underground tunnels for flood mitigation. Chevall Pryce, Houston Chronicle, "Tunnels could be a viable solution to flooding in Houston," 21 Aug. 2019 Though recreational cannabis is legal in California, an underground market exists where users can buy cheap products that are not licensed by the state. Erin Allday, SFChronicle.com, "Unlicensed marijuana vaping products eyed in 20 lung disease cases in Calif.," 21 Aug. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'underground.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of underground

Adverb

14th century, in the meaning defined at sense 1

Noun

1594, in the meaning defined at sense 1

Adjective

1601, in the meaning defined at sense 1

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Statistics for underground

Last Updated

5 Sep 2019

Look-up Popularity

Time Traveler for underground

The first known use of underground was in the 14th century

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More Definitions for underground

underground

adverb

English Language Learners Definition of underground

 (Entry 1 of 3)

: below the surface of the earth
: in or into a place that is hidden or secret : out of the view of the public

underground

noun

English Language Learners Definition of underground (Entry 2 of 3)

British : a system of trains that run below the ground in a large city
: a group of people who secretly work to oppose or overthrow a government

underground

adjective

English Language Learners Definition of underground (Entry 3 of 3)

: located or occurring below the surface of the earth
: secret and usually illegal
: of, relating to, or produced in a social and artistic world that is different and separate from the main part of society

underground

adverb
un·​der·​ground | \ ˌən-dər-ˈgrau̇nd How to pronounce underground (audio) \

Kids Definition of underground

 (Entry 1 of 3)

1 : below the surface of the earth
2 : in or into hiding or secret operation The rebels went underground.

underground

noun
un·​der·​ground | \ ˈən-dər-ˌgrau̇nd How to pronounce underground (audio) \

Kids Definition of underground (Entry 2 of 3)

1 : subway
2 : a secret political movement or group

underground

adjective
un·​der·​ground | \ ˈən-dər-ˌgrau̇nd How to pronounce underground (audio) \

Kids Definition of underground (Entry 3 of 3)

1 : located under the surface of the ground underground pipes
2 : done or happening secretly an underground revolt

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Comments on underground

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