KVM is an acronym for Keyboard, Video, Mouse. It describes a hardware product that allow a keyboard, video display, and mouse to be used by more than one computer, by using a switch to choose the focused computer.
A KVM switch is a hardware product that provides ports to connect a single keyboard, computer mouse, and video display which can be used by more than one computer, but only one computer at a time. The KVM switch typically has numbered buttons or switch positions with which a user chooses which computer will use the keyboard, video, and mouse. This allows one desk setup to support multiple computers with just one set of human interface devices.