theory of relationship between heat and mechanical energy, 1854, from adj. thermodynamic; also see -ics.
thermodynamics ther·mo·dy·nam·ics (thûr'mō-dī-nām'ĭks)
n.
Physics that deals with the relationships between heat and other forms of energy.
Thermodynamic phenomena and processes.
The branch of physics devoted to the study of heat and related phenomena. The behavior of heat is governed by the three laws of thermodynamics: (1) The total energy of an isolated system cannot change; this is the law of conservation of energy. (2) Heat will not flow from a cold to a hot object spontaneously (see entropy). (3) It is impossible, in a finite number of operations, to produce a temperature of absolute zero.
Note: All thermodynamic properties of matter can be understood in terms of the motion of atoms and molecules.