In thermodynamics, heat Q is a transfer quantity that may be defined as the energy which, exchanged by a system, has the effect of modifying its temperature (sensible heat) or inducing a change of state (latent heat). [1]

In human social systems
In human thermodynamics, the definition of heat is the same, however, the terminological transfer and the understanding of generalized state terms, such as "energy" or temperature", and conceptions such as "system" or "latent heat" used in reference to human social systems is a new area of research. How does the sexual heat of reproduction, for instance, related to the definition of heat as energy in transfer? There are many who will argue that the term "heat" used in reference to human life processes is only metaphor. When human systems are defined as consisting of substrate-attached systems of human molecules, however, according to which heat from the sun falls through a temperature gradient to the body of the cold night sky and thereby drives the daily production of human work, the standard definition of heat finds clarification.

Further reading

• Kelland, Philip. (1837). Theory of Heat (182 pgs). London: John W. Parker.
• Maxwell, James C. (1872). Theory of Heat (313 pgs). London: Longmans, Green, and Co.
• Preston, Thomas. (1894). Theory of Heat (719 pgs). London: MacMillan and Co.

References
1. Perrot, Pierre. (1998). A to Z of Thermodynamics, Oxford: Oxford University Press.