geo·​ther·​mal | \ ˌjē-ō-ˈthər-məl How to pronounce geothermal (audio) \

Definition of geothermal

: of, relating to, or utilizing the heat of the earth's interior also : produced or permeated by such heat geothermal steam geothermal regions

Keep scrolling for more

Other Words from geothermal

geothermally \ ˌjē-​ō-​ˈthər-​mə-​lē How to pronounce geothermally (audio) \ adverb

Did You Know?

Geothermal comes partly from the Greek thermos, "hot". Most geothermal electricity is provided by power plants situated in areas where there is significant activity of the Earth's great tectonic plates—often the same areas where volcanoes are found. But hot water from deep underground may be used by cities far from volcanoes to heat buildings or sidewalks. And a newer source of geothermal energy relies on a less dramatic kind of heat: Individual homeowners can now install heat pumps that take advantage of the 50°-60° temperature of the soil near the surface to provide heating in cold weather (and air-conditioning in the warm months). These very small-scale geothermal systems may eventually supply more useful energy than the large power plants.

Examples of geothermal in a Sentence

Recent Examples on the Web

To learn all there is to know about geothermal energy, visit the Dandelion Energy site. Taylor Mead, House Beautiful, "You Can Save Serious Money By Powering Your Home Via Your Backyard," 5 Dec. 2018 Photo: magnus Nilsson One recipe in The Nordic Baking Book shows how a community in Iceland bakes rye bread in the ground using geothermal energy. Howie Kahn, WSJ, "Magnus Nilsson’s ‘The Nordic Baking Book’ is a Bible for Bakers," 12 Oct. 2018 The second was based in Iceland at a geothermal plant that released some volcanic CO2. Megan Geuss, Ars Technica, "Company that sucks CO2 from air announces a new methane-producing plant," 4 Oct. 2018 Thanks to its location on a system of volcanoes, Iceland has enough geothermal power to provide free electricity to its roughly 350,000 inhabitants. Bloomberg, Fortune, "Elon Musk Is a Superstar in Iceland. Here's Why," 9 May 2018 An upgrade to the geothermal system (projected to cost roughly $100,000) is in the works, as is the installation of more solar panels. Harriot Manley,, "Yountville’s Bardessono resort still deeply green — just less vocal about it," 20 June 2018 The house, located at 7979 S. Ford Road, was built in 1992, but it has been updated with modern features, a new roof and new water and geothermal systems. Emma Kate Fittes, Indianapolis Star, "Hot Property: A $2.1 million newly restored, French-inspired Zionsville home," 11 May 2018 The building will use a geothermal cooling and heating system, relying on wells dug 465 feet underground. Keiko Morris, WSJ, "In the Botanical Garden, Construction Workers Tiptoe Quietly," 6 May 2018 The entirety of the project will now include tying the heating system into the college’s geothermal system, changing out the lighting, extending the new carpeting and adding two classrooms, Welch said. Emily K. Coleman, Lake County News-Sun, "College of Lake County's Grayslake campus library to get 'complete face-lift' this summer," 30 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'geothermal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of geothermal

1875, in the meaning defined above

History and Etymology for geothermal

International Scientific Vocabulary

Keep scrolling for more

Learn More about geothermal

Share geothermal

Statistics for geothermal

Look-up Popularity

Time Traveler for geothermal

The first known use of geothermal was in 1875

See more words from the same year

Keep scrolling for more

More Definitions for geothermal



English Language Learners Definition of geothermal

: of, relating to, or using the natural heat produced inside the Earth also : produced by such heat

Comments on geothermal

What made you want to look up geothermal? Please tell us where you read or heard it (including the quote, if possible).


a shady place in a garden or forest

Get Word of the Day daily email!

Test Your Vocabulary

Original Meanings Quiz

  • rembrandt-painting-a-young-scholar-and-his-tutor
  • Which of the following is the earliest known sense of the word awe?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!