Geothermal

Part of speech: adjective

Definitions

1. Relating to or generated by the internal heat of the Earth, especially as a source of energy for heating or electricity production
2. Pertaining to energy derived from the Earth's internal heat sources, which can be harnessed for various applications including electricity generation and heating
3. Connected to the heat originating from within the Earth, utilized for energy production and heating purposes in various technologies

Etymology: Ancient Greek gave English the building blocks for this word long before anyone measured the planet's internal warmth. "Gaia" (γαῖα) was the earth as a living thing, and its shortened form "gê" (γῆ) was the ordinary word for the ground, the soil, or the land. Greek compounds took the combining form "geo-," so "geo-" carries the sense of earth into English words such as geography, the writing of the earth, and geology, the study of its rocks. "Thermal" comes from a different Greek stem, "thermos," meaning hot. English joined it to "geo-" to name heat that rises from beneath the surface. The word is a plain modern compound, assembled from these two Greek elements rather than inherited from any single older English term. Its most familiar use is in power generation, where engineers tap hot rock or steam below ground to drive turbines. The same earth heat also warms hot springs and geysers, so the word can describe both a natural spring and a built plant.

Synonyms: earth heat, geoenergy