energy - (physics) the capacity of a physical system to do work; the units of energy are joules or ergs; "energy can take a wide variety of forms"

geothermal energy - energy derived from the heat in the interior of the earth

heat of dissociation - the heat required for a fluid substance to break up into simpler constituents

heat of formation - the heat evolved or absorbed during the formation of one mole of a substance from its component elements

heat of solution - the heat evolved or absorbed when one mole of a substance is dissolved in a large volume of a solvent

heat of transformation, latent heat - heat absorbed or radiated during a change of phase at a constant temperature and pressure

specific heat - the heat required to raise the temperature of one gram of a substance one degree centigrade