subterranean

adjective

sub·​ter·​ra·​nean ˌsəb-tə-ˈrā-nē-ən 

-nyən

variants or less commonly subterraneous

ˌsəb-tə-ˈrā-nē-əs 

-nyəs

1

: being, lying, or operating under the surface of the earth

2

: existing or working in secret : hidden

a subterranean network of criminals

subterraneanly adverb

or less commonly subterraneously

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Go Underground With Subterranean

A tunnel is a subterranean road or pathway, and a subway is a subterranean railway. The subterranean vaults at Fort Knox hold billions of dollars of gold reserves. Subterranean reservoirs called aquifers are tapped for water; in places where the pressure on the subterranean water is great enough, a hole drilled in the ground will bring it bubbling to the surface.

Synonyms

• belowground
• subsurface
• underground

Examples of subterranean in a Sentence

a subterranean bunker that supposedly could withstand even an atomic blast

Recent Examples on the Web

But influence machines were once subterranean: Few people would have known about the political influence machine that the Koch brothers built in the past several decades if not for the work of investigative journalists. —Ali Breland, The Atlantic, 9 Dec. 2024

While orbiting Jupiter, Clipper will fly by Europa dozens of times and use its array of scientific instruments to study the dynamics of the moon’s subterranean ocean and look for organic compounds, a potential indicator of life. —Noah Haggerty, Los Angeles Times, 14 Oct. 2024

And this is an apt name for this chapter as all the traumatized denizens of the bunkers suffer restrictions from barricades, both physical and emotional, as their unnatural subterranean life seems to be cartwheeling out of control since Juliette took a stroll outside. —Jeff Spry, Space.com, 23 Dec. 2024

Inside Llewyn Davis, The Marvelous Mrs. Maisel, and A Complete Unknown immerse us in intimate, sometimes subterranean performance spaces. —David Browne, Rolling Stone, 22 Dec. 2024

Word History

Etymology

Latin subterraneus, from sub- + terra earth — more at thirst

First Known Use

1603, in the meaning defined at sense 1

Kids Definition

subterranean

adjective

sub·​ter·​ra·​nean ˌsəb-tə-ˈrā-nē-ən 

-nyən

1

: being, lying, or operating under the surface of the earth

2

: existing or working in secret : hidden