Wikipedia
A hypervisor (or virtual machine monitor, VMM) is computer software, firmware or hardware that creates and runs virtual machines A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems Multiple instances of a variety of operating systems may share the virtualized hardware resources: for example, Linux, Windows, and macOS instances can all run on a single physical x86 machine This contrasts with operating-system-level virtualization, where all instances (usually called containers) must share a single kernel, though the guest operating systems can differ in user space, such as different Linux distributions with the same kernel
Hypervisor - Wikipedia, the free encyclopedia