A thermodynamic system is a specific portion of the universe that is being studied, separated from its surroundings by a boundary. This system can exchange energy and matter with its environment, and it can be classified into three main types: open systems, closed systems, and isolated systems. Open systems can exchange both energy and matter, closed systems can exchange energy but not matter, and isolated systems do not exchange either. Understanding thermodynamic systems is essential in fields like physics, engineering, and chemistry. These systems help analyze processes such as heat transfer, work done, and changes in energy, which are crucial for designing engines, refrigerators, and other technologies.