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

Did you know?

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 of subterranean

• underground

Examples of subterranean in a Sentence

a subterranean bunker that supposedly could withstand even an atomic blast

Recent Examples on the Web

Today, scientists believe these subterranean formations could offer a reliable solution to the clean energy transition’s biggest storage challenge. — Mrigakshi Dixit, Interesting Engineering, 29 Sep. 2026

Make sure to check the hotel’s calendar of events for poetry readings and artist talks, which are often held in the subterranean B Bar speakeasy off the lobby bar. — Condé Nast, Condé Nast Traveler, 29 Sep. 2026

Throughout—and even echoed in the staff’s smart wardrobe—there’s a sophisticated color palette of taupe, seafoam, and rich Bordeaux reds, perhaps a nod to the owner’s extensive wine collection, housed in three subterranean cellars. — Nicole Trilivas, Travel + Leisure, 29 Sep. 2026

These subterranean incursions pose severe risks to public safety, essential utility grids and critical transit infrastructure. — Voice Of The People, New York Daily News, 28 Sep. 2026

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