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

There would be subterranean and above-ground parking, and at least 20% of the units are expected to be designated as affordable with subsidized rents. —Roger Vincent, Los Angeles Times, 2 Nov. 2024

An upscale hotel and spa — featuring a juice bar and multiple subterranean pools — is set to open on NE Alberta Street with spa services coming this month and the hotel opening next year. —Axios Portland, Axios, 1 Nov. 2024

But the most remarkable discovery came from Galileo’s magnetometer, which found that a conductive layer in Europa was generating a local magnetic field as the moon passed through Jupiter’s magnetosphere—something that could most readily be explained by the presence of a briny, subterranean ocean. —Jay Bennett, Smithsonian Magazine, 14 Oct. 2024

Elsewhere is a subterranean four-car garage with an accompanying fitness center. —Wendy Bowman, Robb Report, 25 Oct. 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