
A router is a device in computer networking that forwards data packets to their destinations, based on their addresses. The work a router does it called routing, which is somewhat like switching, but a router is different from a switch. The latter is simply a device to connect machines to form a LAN.
More technically, a [...]

A domain name is an identification label that defines a realm of administrative autonomy, authority, or control in the Internet, based on the Domain Name System (DNS).
Domain names are used in various networking contexts and application-specific naming and addressing purposes. They are organized in subordinate levels (subdomains) of the DNS root domain, which is nameless. [...]

The Internet, sometimes called simply “the Net,” is a worldwide system of computer networks – a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers). It was conceived by the Advanced Research Projects Agency [...]