Difference Between LAN & WAN in Wireless Routers
Many wireless routers display a reference to LAN and/or WAN. These refer to a local area network and a wide area network respectively, with the latter usually being a synonym for the Internet itself. These terms should not be confused with WLAN, which is a wireless local area network.
A local area network is one where all the computers are in the same general location. This can mean all in the same office or building, or in a group of nearby buildings. The key is that these computers are usually connected by a single cable, a small collection of cables or a local Wi-Fi connection. This setup means the networks tend to have fast connection speeds allowing for quick data transfers.
A wide area network is one that covers a much bigger region than a local area network, which could be across a town, a region, a country or the entire world. Though there's no commonly-agreed precise cutoff point between a LAN and a WAN, a WAN tends to use "external" cabling such as a phone network or a cable company's fiber optic network. Unlike a LAN, a WAN is usually owned and operated by a different organization to the people and organizations that use the network to send and receive data. Usually a WAN will have slower data transfer speeds than a LAN. A WAN uses different technology to a LAN for transferring and routing data, though ordinary users who aren't technical administrators won't usually need to worry about this.
In the context of a wireless router, the WAN in question is almost always the Internet itself. A router may have one or more LAN ports into which the users plug computers and other devices that need an Internet connection. The router will also have a WAN port, which is the connection point for the cable that runs either into a modem or directly to a telephone or cable socket for connecting to the Internet. Although almost all routers have a WAN port, some may use a different label such as simply "Internet." The only routers that would not have such a port would be those set up so that computers can connect to one another to share data, but cannot connect to the Internet, for example if the data is confidential and users don't need Internet access.
The term WAN could be confused with WLAN, or wireless local area network. A WLAN is a type of LAN that uses wireless technology (nearly always Wi-Fi) to connect some or all computers and devices to the router, and in turn to one another and the Internet. All wireless routers support setting up a WLAN, though many can also allow devices to connect via a cable as well.