An Operating System (OS) is the fundamental software that manages a computer’s hardware resources and provides essential services for running applications. It acts as an intermediary between the user, application programs, and the computer hardware, ensuring that tasks such as memory allocation, file management, and device control are handled efficiently. Popular examples include Windows, macOS, and Linux. The OS is crucial for system stability, security, and usability, making it possible for users and software to interact seamlessly with the physical components of a device.