(Wide Area Network port) The socket on a network device that is wired to an external network, which is typically the Internet. In the home and small business, a WAN port is an RJ-45 Ethernet port on a router that is wired to a cable or DSL modem. On small routers, the WAN port may be labeled simply "Internet." In the larger enterprise, a WAN port may hook up to a T3 line or other wide area network service. Contrast with LAN port. See RJ-45.