A Wide Area Network, or WAN, is a computer network that spans a large geographical area. A WAN can connect several smaller networks, such as Local Area Networks (LAN) or Metropolitan Area Networks (MAN).
Organizations often use WANs with multiple locations, such as businesses with offices in different cities or schools with campuses in different states. Using a WAN, these organizations can share data and resources between their locations.
WANs can be implemented using either dedicated leased lines or the public Internet. Dedicated leased lines are private connections that are owned by the organization using them. The public Internet is less expensive but may be less reliable than dedicated leased lines.