A context switch is a process in computing where the CPU (Central Processing Unit) switches from executing one process or thread to another. This involves saving the state of the current process, including its registers and program counter, so it can be resumed later. The operating system manages these switches to ensure efficient multitasking and resource allocation. During a context switch, the operating system's scheduler determines which process to run next based on various factors like priority and resource needs. This allows multiple processes, such as applications or services, to share the CPU effectively, improving overall system performance and responsiveness.