<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Relevant discussion may be found on the talk page . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Relevant discussion may be found on the talk page . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2014) (Learn how and when to remove this template message) </Td> </Tr> <P> Thermal energy is a term used loosely as a synonym for more rigorously - defined thermodynamic quantities such as the internal energy of a system; heat or sensible heat, which are defined as types of transfer of energy (as is work); or for the characteristic energy of a degree of freedom in a thermal system k T (\ displaystyle kT), where T (\ displaystyle T) is temperature and k (\ displaystyle k) is the Boltzmann constant . </P> <P> Heat is energy transferred spontaneously from a hotter to a colder system or body . Heat is energy in transfer, not a property of the system; it is not' contained' within the boundary of the system . On the other hand, internal energy is a property of a system . In an ideal gas, the internal energy is the statistical mean of the kinetic energy of the gas particles, and it is this kinetic motion that is the source and the effect of the transfer of heat across a system boundary . For this reason, the term "thermal energy" is sometimes used synonymously with internal energy . (Heat and work depend on the way in which an energy transfer occurred, whereas internal energy is a property of the state of a system and can thus be understood even without knowing how the energy got there .) The term "thermal energy" is also applied to the energy carried by a heat flow,, although this quantity can also simply be called heat or amount of heat . </P>

Which is the us english term for thermal energy
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