geothermal.

Relating to heat from inside the earth or another planet.

Use it for

Words that belong together

• geothermal energy
• geothermal vent

On the page

The settlement relied on geothermal energy during the long winter.

Usage notes

Primary category: sci-fi. Forms: Normally non-gradable; no ordinary comparative or superlative. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Commonness: moderately common.