The phrase "subterranean ocean" refers to a large body of water that exists underground, beneath the Earth's surface.
Sentences with «subterranean ocean»
Jupiter's moon Europa features a warm subterranean ocean covered in ice. (gizmodo.com)
Saturn's moon Enceladus features a warm subterranean ocean covered in ice. (gizmodo.com)
It is probably generated when water in the moon's subterranean ocean reacts with rock in its core, researchers report in the April 14 Science. (sciencenews.org)