Wiktionary
n. (context physics English) a property, characteristic of the state of a thermodynamic system, the change of which is equal to the heat absorbed minus the work done by the system
Wikipedia
In thermodynamics, the internal energy of a system is the energy contained within the system, including the kinetic and potential energy as a whole. It keeps account of the gains and losses of energy of the system that are due to changes in its internal state.
The internal energy of a system can be changed by transfers of matter and by work and heat transfer. When matter transfer is prevented by impermeable containing walls, the system is said to be closed. Then the first law of thermodynamics states that the increase in internal energy is equal to the total heat added plus the work done on the system by its surroundings. If the containing walls pass neither matter nor energy, the system is said to be isolated and its internal energy cannot change. The first law of thermodynamics may be regarded as establishing the existence of the internal energy.
The internal energy is one of the two cardinal state functions of the state variables of a thermodynamic system.
Usage examples of "internal energy".
Mind cores had their own internal energy sources) but even the most brutal aggressor would far rather lay siege to that keep-core in the knowledge that the information contained within must surely fall to it eventually, than just destroy it.
The problem is, of course, that is also causes a high dissipation of internal energy: energy is being squandered.
Pushing hard, I wove some of the external Force with my internal energy and tried to see if I could find a spark of Master Skywalker in his body.
Lower the internal energy production, and you would lower the overall temperature.
This vessel does not have the internal energy flows of an interstellar ship.
Then, from a million years' experience, I opened the right-hand thrust damper slightly, selected the PRIMARY energy feed and INTERNAL energy source, switched the gravitation boost to ON, and touched three of the five primer switches.