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.
Examples of subterranean in a Sentence
a subterranean bunker that supposedly could withstand even an atomic blast
Recent Examples on the Web
The spa There’s a dreamy subterranean spa with all the standard treatments, but to really get into Potato Head’s groove, opt for a session at the New Age-y Sanctuary Wellness Centre instead.
—
Condé Nast,
Condé Nast Traveler,
1 July 2026
The hotel reopened in late 2025 as a 28-room property with a subterranean spa housing indoor and outdoor pools, two indoor saunas, a steam room and a hammam, all carved into what was once the monastery’s cellar and crypt.
—
Winston Ross,
Forbes.com,
30 June 2026
About two-thirds of the 6,700 feet of 16 inch steel pipe beneath the river and crossing parts of the two parks would run through subterranean tunnels drilled by a high tech boring machine.
—
Edmund H. Mahony,
Hartford Courant,
29 June 2026
One type of subterranean termite worth noting is the Formosan termite (Coptotermes formosanus).
—
Arricca Elin Sansone,
Southern Living,
25 June 2026
See All Example Sentences for subterranean
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Condé Nast,
Condé Nast Traveler,
1 July 2026
The hotel reopened in late 2025 as a 28-room property with a subterranean spa housing indoor and outdoor pools, two indoor saunas, a steam room and a hammam, all carved into what was once the monastery’s cellar and crypt.
—
Winston Ross,
Forbes.com,
30 June 2026
About two-thirds of the 6,700 feet of 16 inch steel pipe beneath the river and crossing parts of the two parks would run through subterranean tunnels drilled by a high tech boring machine.
—
Edmund H. Mahony,
Hartford Courant,
29 June 2026
One type of subterranean termite worth noting is the Formosan termite (Coptotermes formosanus).
—
Arricca Elin Sansone,
Southern Living,
25 June 2026
See All Example Sentences for subterranean
Cite this Entry
“Subterranean.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/subterranean. Accessed 5 Jul. 2026.
Copy CitationKids 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
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