wifi is a facility which can connect smartphones, laptops, and other gadgets to the internet
Wi-Fi is a local area wireless computer networking technology that allows computers and other devices to communicate over a wireless signal. Wi-Fi can be less secure than wired connections, such as Ethernet, precisely because an intruder does not need a physical connection.
Nearly all modern computers have built-in Wi-Fi chips that allows users to find and connect to wireless routers. However, the router must be connected to the Internet (via a DSL or cable modem) in order to provide Internet access to connected devices.