A device that appears to the user as a separate entity, but is actually a shared portion of a real device.
see virtual semiconductor device.
n. A device that can be referenced but that does not physically exist. Virtual-memory addressing, for example, uses magnetic disk storage to simulate memory larger than that physically available.
A virtual device in Unix is a file such as :/dev/null or :/dev/urandom, that is treated as a device, as far as user level software is concerned, but is generated by the kernel without reference to hardware.