Physical network
From Computer History Wiki
A physical network is the term used for a single network which is able to transmit data directly from a source network interface to a destination interface; an example of such a physical network is an Ethernet.
(Early internetwork work used the term subnet, but this term fell out of use for this meaning when it was taken over to mean something else.)
Internetworks ('internets' for short) are built by connecting together a number of physical networks using packet switches (called 'routers'), and using an internetwork protocol to be able to send traffic from a host on any physical network to one on any other.
