The following are some definitions the student should know in order to understand the language of thermodynamics.
System: A defined physical space, whose boundaries usually correspond to some physical barrier or logical limit. Examples
Isolated System: A system which is entirely uninfluenced by changes outside the system. In particular, there is no possibility of the transfer of either energy or matter across the boundaries of the system. Detail
Closed System: A system in which there is the possibility of energy exchange with the environment, but there is no transfer of matter across the boundaries. This does not exclude the possibility of a change of internal composition due to chemical reaction. Detail
Open Systems: A system which can exchange both energy and matter with its environment. Detail