thermo-, therm-, thermi-, -thermia, -therm, -thermal, -thermic, -thermias, -thermies, -thermous, -thermy
(Greek: heat, heating, heater, hot, warm)
The term heat is employed in ordinary language in different senses. Some scientists distinguish four principal applications of the term:
- Sensation of heat.
- Temperature, or degree of hotness.
- Quantity of thermal energy.
- Radiant heat, or energy of radiation.
2. Relating to the external warmth of the body.
3. A compound that liberates heat during its formation and which absorbs heat or energy during its decomposition.
4. Characterized by, or attended by, the development of heat; such as, combustion.
2. A line connecting points of equal or constant temperatures on the surface of the earth.
2. A thermometer constructed to measure temperatures in boreholes to provide information about the temperature range within which minerals were developed.
2. Describing an energy system that makes use of the internal heat produced by the earth.
You may see more information about geothermal drilling here.
2. Heat which is produced mainly by the decay of naturally occurring radioactive isotopes of thorium, potassium, and uranium in the earth's core.
3. An energy produced by tapping the earth's internal heat. At present, the only available technologies to do this are those that extract heat from hydrothermal convection systems, where water or steam transfer the heat from the deeper part of the earth to the areas where the energy can be tapped.
The amount of pollutants found in geothermal vary from area to area but may contain arsenic, boron, selenium, lead, cadmium, and fluorides. They also may contain hydrogen sulphide, mercury, ammonia, radon, carbon dioxide, and methane.
Getting the Earth's Heat
Geothermal power plants, which tap hot subterranean water or steam, are high on the lists of at least thirty states in the U.S. which are requiring utility companies to generate some portion of their electricity from such renewable sources.
Most utilities have not pursued geothermal energy primarily because up-front costs, including exploratory drilling, can be expensive since geothermal taps deep reservoirs, not groundwater, which collects much closer to the surface.
An extensive study recently released by the Massachusetts Institute of Technology has shown that the heat available under ground is surprisingly plentiful nationwide.
More information about special Geothermal Energy sources.

Related "heat, hot" word units: ferv-; pyreto-.
Related "bubble" word unit: ebulli-.