Short for "Wireless Fidelity." Wi-Fi refers to wireless networking technology that allows computers and other devices to communicate over a wireless signal. It describes all network components that are based on one of the 802.11 standards, including 802.11a, 802.11b, 802.11g, and 802.11n. These standards were developed by the IEEE and adopted by the Wi-Fi Alliance, which trademarked the name "Wi-Fi".
Wi-Fi is the standard way computers connect to wireless networks. Nearly all computers now have built-in Wi-Fi cards that allows users to search for and connect to wireless routers. Many mobile devices, video game systems, and other standalone devices also include Wi-Fi capability, enabling them to connect to wireless networks as well. These devices may be able to connect to the Internet using a Wi-Fi signal. However, it is important to understand that the Wi-Fi connection only exists between the device and the router. Most routers are connected to a DSL or cable modem, which provides Internet access to all connected devices.
Since Wi-Fi is a wireless networking standard, any device with a "Wi-Fi Certified" wireless card should be recognized by any "Wi-Fi Certified" access point, and vice-versa. However, wireless routers can be configured to only work with a specific 802.11 standard, which may prevent older equipment from communicating with the router. For example, some 802.11n routers can either be configured to only work with 802.11n devices. If this option is chosen, 802.11g devices will not be able to connect to the router, even though they are Wi-Fi certified.