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
Giant subterranean sandworms measuring 1,500 feet long; a narcotic that fuels interstellar travel and bends a user’s perception of space-time; a mystical cabal of eugenicist witches—the list goes on.
—
Andrew Paul, Popular Science, 19 Mar. 2026
Accessed via a brick staircase in the garden, the subterranean passages run beneath the house and grounds, forming a series of chambers carved out centuries ago as part of a sand mine.
—Abby Montanez, Robb Report, 17 Mar. 2026
Aire Ancient Baths A subterranean theater of candlelit pools and vaulted brick, Aire remains one of the city’s few strictly phone-and-camera-free refuges.
—Amy Louise Bailey, Travel + Leisure, 12 Mar. 2026
Today, folks come from all over the world to relax in its 43,000-square-foot subterranean spa or see the festive gingerbread competition each December.
—Tara Massouleh McCay, Southern Living, 12 Mar. 2026
See All Example Sentences for subterranean
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Andrew Paul, Popular Science, 19 Mar. 2026
Accessed via a brick staircase in the garden, the subterranean passages run beneath the house and grounds, forming a series of chambers carved out centuries ago as part of a sand mine.
—Abby Montanez, Robb Report, 17 Mar. 2026
Aire Ancient Baths A subterranean theater of candlelit pools and vaulted brick, Aire remains one of the city’s few strictly phone-and-camera-free refuges.
—Amy Louise Bailey, Travel + Leisure, 12 Mar. 2026
Today, folks come from all over the world to relax in its 43,000-square-foot subterranean spa or see the festive gingerbread competition each December.
—Tara Massouleh McCay, Southern Living, 12 Mar. 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 22 Mar. 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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