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

Next year, a subterranean, London-social-club-style complex of lounges called the Bunker Suites is expected to open. — Ben Ryder Howe, Curbed, 21 Aug. 2026

The subterranean restaurant serves up some of the city’s most sophisticated noodles, and a real summer treat is the cucumber gazpacho ramen ($22), served cold. — Anne Ewbank, Sacbee.com, 19 Aug. 2026

No matter the time of year, there’s no shortage of iconic attractions in Edinburgh, from its massive castle to Calton Hill and Mary King’s Close, a subterranean living museum beneath the Royal Mile. — Paul Jebara, Condé Nast Traveler, 18 Aug. 2026

North Korean military engineers—renowned for building massive subterranean installations—also helped Iran design and construct hardened missile silos, underground networks, and nuclear facility bunkers. — Charlie Campbell, Time, 17 Aug. 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