The relationship between heat and other forms of energy and also their study is known as Thermodynamics.
“Thermo” means heat and “Dynamics” means movement or transfer, so we can say that thermodynamics is the transfer of heat.
The various thermodynamics terms are System, Surroundings, and Boundary.
Thermodynamic terms:-
System: The confined portion of the universe separated for thermodynamic study is called as a system.
Surroundings: Everything outside the universe is called the surroundings, and once a system is defined, the surroundings will be defined automatically.
Boundary: The real or the imaginary surface of the system which separates the system from the surroundings is called as the boundary.
Therefore, the study of the relation between heat and other forms of energy is called thermodynamics.