WAN stands for Wide Area Network.

The Internet is an example of a WAN.

Corporations and organizations can create their own WAN by connecting the various LAN (Local Area Networks) together. WANs and LANs are connected to each other via a router.

If you have offices in Los Angeles, New York City and Atlanta, they can all share common data by creating a WAN. Access for the WAN would be through the telephone lines or Internet Service Providers.