geothermal

American  

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

Or geothermic

adjective

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

---

geothermal British  

/ ˌdʒiːəʊˈθɜːməl /

adjective

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

---

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.

---

Etymology

Origin of geothermal

First recorded in 1870–75; geo- + thermal

Example Sentences

Scientists suspect that warmer geothermal sources once existed beneath these areas, producing the conditions needed to create this mineral.

From Science Daily • Mar. 10, 2026

These results indicate that geothermal heat likely altered the minerals after they were deposited.

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

The renewable-energy company inked a recent deal to sell geothermal power to Google’s growing operations in Nevada.

From The Wall Street Journal • Feb. 25, 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