The acronym WAN stands for wide area network. Unlike a metropolitan area network (MAN), a WAN is not restricted to a particular geographical area but may be confined within the bounds of a country. It allows connection between several local area networks, (LANs) and it's relatively costly to set up.
In telecommunications, there are usually three types of networks: LAN, MAN and WAN. These networks are identified depending on their coverage area. A LAN serves a small area, such as a school or a site. A MAN is a larger network that covers several buildings in a town or city. A WAN serves a wide geographical area, and most are composed of several LANs.
A WAN is usually limited to organizations and businesses, although they may also be accessed by the public. A good example of a public WAN is the Internet. Organizations and governments use WANs to convey data among suppliers, customers and employees. This allows organizations to carry out daily activities regardless of location.
In computer networking, a WAN may be viewed as a technology that is used to send data over long distances between various LANs, MANs or other networking architectures. Most WANs are built using satellite links, Internet or point-to-point connections between two LANs or computers (leased lines).