An "open system" refers to a system that interacts with its environment by exchanging energy, matter, or information. This means that the system is not isolated; it can receive inputs and produce outputs. Examples of open systems include ecosystems, where organisms interact with their surroundings, and businesses that engage with customers and suppliers. In contrast to closed systems, which do not exchange matter with their environment, open systems are dynamic and adaptable. They can respond to changes in their environment, making them more flexible. Understanding open systems is essential in fields like biology, engineering, and economics, where interactions play a crucial role in system behavior.