Branch of Physics that  deals with relation of Heat and other forms of Energy.
1 4 1
Thermodynamics is a branch of physics concerned with heat and temperature and their relation to energy and work. It defines macroscopic variables, such as internal energy, entropy, and pressure, that partly describe a body of matter or radiation. It states that the behavior of those variables is subject to general constraints, that are common to all materials, not the peculiar properties of particular materials. These general constraints are expressed in the four laws of thermodynamics.
"Thermo-dynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies, and the relation of heat to electrical agency."
In greek :Thermo - heat ; dynamics- the branch of mechanics concerned force or property which stimulate the process. THERMODYNAMICS is the branch of physics; it explains the physical science that deals with the relations between heat/radiation and other forms of energy .roughly you can say that its a study's related to converting or conversion of heat into differnt forms of energy.