geothermal

American  

[jee-oh-thur-muhl] / ˌdʒi oʊˈθɜr məl /

Or geothermic

adjective

1. of or relating to the internal heat of the earth.

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geothermal British  

/ ˌdʒiːəʊˈθɜːməl /

adjective

1. of or relating to the heat in the interior of the earth

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geothermal Scientific  

/ jē′ō-thûr′məl /

1. Relating to the internal heat of the Earth. The water of hot springs and geysers is heated by geothermal sources.

2. ◆ 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.

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Etymology

Origin of geothermal

First recorded in 1870–75; geo- + thermal

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.

Example Sentences

The catch is that a suitable subsoil is required, and that deep geothermal energy in particular can be hampered by high costs and uncertainties.

From Barron's • Apr. 24, 2026

Heating with geothermal energy, lighting with solar panels, cooking with biodegradable waste: how can we live with less oil and gas?

From Barron's • Apr. 24, 2026

The findings indicate that volcanic heat at the Juventae Plateau and geothermal energy beneath Aram Chaos could convert common hydrated sulfates into ferric hydroxysulfate.

From Science Daily • Mar. 10, 2026

She said the cost of deep geothermal is comparable to other forms of electricity generation, but a lot of spend is upfront.

From BBC • Feb. 26, 2026

At the center of the camp, water from a geothermal well had been piped into a pair of shallow, steaming pools lined with rocks and shaded by palm trees: Oh-My-God Hot Springs.

From "Into the Wild" by Jon Krakauer