USENET is not
a physical network, but rather a logical network resting on top of several existing
physical networks. These networks include, but are not limited to, UUCP, the ARPANET,
an Ethernet, the BLICN network, an NSC Hyperchannel, and a Berknet.
- Mark Horton; Standard for Interchange of USENET Messages;
RFC 850; June 1983.