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

• underground

Examples of subterranean in a Sentence

a subterranean bunker that supposedly could withstand even an atomic blast

Recent Examples on the Web

Fortunately, one of those admitted was filmmaker Werner Herzog, who was granted permission to bring small cameras into the subterranean limestone system to make a documentary. —Matthew Carey, Deadline, 4 Sep. 2025

Things to Do Explore the Shenandoah Caverns Go beneath the surface at Shenandoah Caverns, a fascinating subterranean attraction. —Tykesha Spivey Burton, Southern Living, 3 Sep. 2025

Randy Tufts and Gary Tenen squeezed through a small opening in the Whetstone Mountains of southern Arizona and entered a magical subterranean world, an untouched wet, living cave. —Roger Naylor, AZCentral.com, 29 Aug. 2025

Saaqi, a subterranean bar, and an Chef’s Studio experience. —Melissa Kravitz Hoeffner, Forbes.com, 28 Aug. 2025

Word History

Etymology

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

First Known Use

1603, in the meaning defined at sense 1

Rhymes for subterranean

• romanian
• roumanian
• rumanian
• ukrainian
• cenomanian
• lithuanian
• pennsylvanian
• pomeranian
• mediterranean

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