definition of thermodynamics

System: A collection of material, or region in space, set aside for thermodynamic investigation. The system is chosen by the investigator.
Boundary: Surface or surfaces, real or imaginary, by which either a closed or open system is delineated from the surroundings for analysis.
Surrounding(Environment): Material, or regions in space, outside the boundaries of the system(s) but which may interact and influence system behavior. Usually limited to interactions with the system.
Closed system: A system that does not exchange mass with its surroundings.
Open system: A system that exchanges mass with its surroundings.
Isolated system: A system that does not interact with the environment. Changes of conditions in the environment have no influence on the behavior of isolated systems.
Adiabatic system: A system that has no thermal interaction between system and surroundings. In practice, a thick layer of insulation material approximates an adiabatic wall. The adiabatic system may experience interactions other than thermal.
Property: A property is a macroscopic characteristic of the system (mass, volume, energy, pressure, temperature, specific volume). A certain quantity is a property if, and only if, its change between two states is independent of the process (history).
Thermodynamic property: A particular property from among the larger set on the basis of experiment and experience, has been found to be important for thermodynamic analysis.
Extensive property: One whose numerical value depends on the extent of the system. In a homogeneous system, it is proportional to the mass of the system, e.g. volume, area, length,
energy.
Intensive property: One whose numerical value is independent of the extent of the system, e.g. density, pressure, stress, temperature.
Temperature: The property of a system that determines whether or not it is in thermal equilibrium with another system.
Energy: A quantity that has the capacity for producing a change of state in a closed system.
Work: A form of energy transfer. Work occurs when a force acts over a displacement.
Heat Transfer: Another form of energy transfer. The energy transferred between systems, or between a system and it’s surrounding, due to a temperature difference.
Dimension: An independent quantity that describes a system, a property of a system, or is necessary in the analysis of a system. e.g. time, length, area, volume, mass, temperature, force, energy.

Thermodynamic state: The condition or circumstances of a system as described by values of its thermodynamic properties. The minimum set of independent thermodynamic properties sufficient to describe the state of the system is sometimes called the thermodynamic coordinates.