Of or relating to the internal heat of the earth.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "geothermal" in a sentence
"In fact, the word "geothermal" comes from the Greek words geo (Earth) and therme"
"Operating upon principles found in geothermal technology, this system is even more efficient than radiant flooring."
"I am so impressed with all the latest technology in geothermal energy-it makes so much sense using the natural resources under the earth for clean, efficient and renewable energy."