Final answer:
The supervisor program in an OS is termed the kernel, which controls system resources and facilitates communication between hardware and software.
Step-by-step explanation:
The supervisor program in an operating system (OS) is called the kernel. The kernel is the core part of an operating system and has complete control over everything in the system. It is responsible for managing the system's resources and allows hardware and software to communicate with each other. For example, when you run a program, the kernel allocates memory to the program, manages the program's requests for input/output operations, and ensures that other programs get a fair opportunity to run through a process known as multitasking.