An operating system is a fundamental component of any computer system that manages hardware and software resources. There are different synonyms used for the term operating system, including OS, platform, kernel, system software, software environment, and executive. An OS acts as a bridge between the user and the computer, allowing users to interact with programs, files, and devices by providing an interface to access system resources. The kernel of an OS is responsible for handling system calls and managing the hardware resources like memory, CPU, and disk space. The term platform refers to the hardware and software environment that an OS operates on, while system software and executive refer to the low-level programs that control the system's operation.