Wi-Fi means Wireless Fidelity. It is a wireless technology. Some organisation offers Wi-Fi facility. Here we can connect internet wirelessly over short distance, using Wi-Fi enabled devices.
It uses radio waves to transmit information across a network in a range 2.4 GHz to 5 GHz in short distance. Nowadays this technology is used to access internet in campuses, hypermarkets, hotels by using Laptops, Desktops, tablet, mobile phones etc.