Wi-Fi Definition: What is Wi-Fi. Wi-Fi is the name of a wireless networking technology that uses radio waves to provide high-speed network and Internet connections.This Webopedia Did You Know... article explains Wi-Fi technology: how it works and misconceptions about Wireless Fidelity.i-Fi is simply a trademarked term meaning IEEE 802.11x. The false notion that the brand name Wi-Fi is short for wireless fidelity has spread to such an extent that even industry leaders have included the phrase wireless fidelity in a press release.