subterranean

American  

[suhb-tuh-rey-nee-uhn] / ˌsʌb təˈreɪ ni ən /

adjective

1. existing, situated, or operating below the surface of the earth; underground.

2. existing or operating out of sight or secretly; hidden or secret.

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noun

1. a person or thing that is subterranean.

2. a subterrane.

subterranean British  

/ ˌsʌbtəˈreɪnɪən /

adjective

1. Also: subterraneous.   subterrestrial.  situated, living, or operating below the surface of the earth

2. existing or operating in concealment

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Other Word Forms

• subterraneanly adverb
• subterraneously adverb

Etymology

Origin of subterranean

1595–1605; < Latin subterrāne ( us ) ( subterrane ) + -an

Example Sentences

The subterranean passage was part of Horsley Towers in Leatherhead, a grand mansion once lived in by Lovelace, also the only legitimate child of scandalous 19th Century poet Lord Byron.

From BBC

Engineers with excavating equipment would be needed to dig through the tons of debris blocking entrances to Iran’s subterranean nuclear complexes and check for mines and booby traps.

From The Wall Street Journal

And when it comes to the legacy of Mount Vesuvius — able to change the sky and move the earth — history encompasses all that’s above and plenty that’s subterranean, too.

From Los Angeles Times

But you sense subterranean levels of weirdness that hint that he’s already got ideas for a sequel.

From Los Angeles Times

The proposals included a two-storey "subterranean suite" beneath the No 10 garden, featuring a 200-seat conference room that could double as a "safe haven" in the event of a terror attack.

From BBC