geothermal
Americanadjective
adjective
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Relating to the internal heat of the Earth. The water of hot springs and geysers is heated by geothermal sources.
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◆ Geothermal energy is power generated from natural steam, hot water, hot rocks, or lava in the Earth's crust. In general, geothermal power is produced by pumping water into cracks in the Earth's crust and then conveying the heated water or steam back to the surface so that its heat can be extracted through a heat exchanger, or its pressure can be used to drive turbines.
Etymology
Origin of geothermal
Explanation
Heat that rises from the center of the earth is geothermal. If you ever have the chance to dip your toes in a natural hot spring, you can feel that geothermal warmth for yourself! Anything that's thermal has to do with heat, from the Greek therme. The prefix geo-, or "earth," makes it clear that this type of heat rises from the planet itself. Hot springs are warmed by geothermal energy. Geothermal energy is also a renewable source of heat and power. Many buildings use geothermal heating and it's also a good way to generate electricity.
Vocabulary lists containing geothermal
Elements of the Universe: Geo ("Earth")
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Australia and New Zealand - Middle School and High School
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2015 Spelling Bee - Words from Round 2
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Geothermal energy systems require electronics that can function deep underground, where surrounding rock can glow red-hot.
From Science Daily • Apr. 7, 2026
Geothermal energy offers baseload power, while nuclear fusion, though promising, is considered at least 10 years from commercial viability.
From Barron's • Jan. 23, 2026
His picks include AKR Corporindo, which stands to benefit from a rise in FDI, and Pertamina Geothermal Energy and Alamtri Resources, which are supporting Indonesia’s renewable energy push.
From The Wall Street Journal • Jan. 19, 2026
Geothermal currently represents only a small fraction of energy supplies in the country — about 0.4% of total U.S. utility-scale electricity generation, according to the U.S.
From Los Angeles Times • Aug. 27, 2025
Geothermal wells are usually constructed with carbon steel, she explains, but that quickly loses strength when temperatures exceed 200°C.
From BBC • Oct. 17, 2024
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
