say it: jee-oh-THUR-muhl
geothermal is an adjective meaning "of or relating to the heat in the interior of the earth". It carries one recorded sense.
of or relating to the heat in the interior of the earth
Definitions, synonyms and semantic relations for geothermal come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.