What is a common boundary where different parts of a system interact?

A common boundary where different parts of a system interact is referred to as an interface. This interface can be physical, such as the junction between two mechanical components, or conceptual, like the protocols that govern data exchange between software systems. Interfaces are crucial for ensuring effective communication and functionality between the interacting parts, enabling them to work together cohesively. Effective management of these boundaries is essential for system performance and integration.