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.
Examples of subterranean in a Sentence
a subterranean bunker that supposedly could withstand even an atomic blast
Recent Examples on the Web
Clark Kent and Lois Lane (Phyllis Coates) arrive in a small town to report on the world’s deepest oil well, which is handy for the town because the well is home to subterranean creatures and Clark Kent is secretly Superman.
—
Rory Doherty, Vulture, 11 July 2025
The second smallest is a subterranean snail from Spain, Czaja said.
—Miami Herald, 11 July 2025
Once a royal residence turned military stronghold, its subterranean spaces include powder magazines and storerooms that played a vital role in its defense, illustrating medieval fortification architecture.
—Joseph V Micallef, Forbes.com, 8 July 2025
The team believes accessing such subterranean magma would take a similar approach to that of geothermal energy production — which harnesses heat from the Earth’s core and is a significant source of energy in Iceland.
—Francesca Perry, CNN Money, 3 July 2025
See All Example Sentences for subterranean
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Rory Doherty, Vulture, 11 July 2025
The second smallest is a subterranean snail from Spain, Czaja said.
—Miami Herald, 11 July 2025
Once a royal residence turned military stronghold, its subterranean spaces include powder magazines and storerooms that played a vital role in its defense, illustrating medieval fortification architecture.
—Joseph V Micallef, Forbes.com, 8 July 2025
The team believes accessing such subterranean magma would take a similar approach to that of geothermal energy production — which harnesses heat from the Earth’s core and is a significant source of energy in Iceland.
—Francesca Perry, CNN Money, 3 July 2025
See All Example Sentences for subterranean
Cite this Entry
“Subterranean.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/subterranean. Accessed 16 Jul. 2025.
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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