Wi-Fi is the wireless networking technology commonly used to connect devices to local networks over radio.
Modern Wi-Fi devices can operate in several unlicensed bands, especially 2.4 GHz and 5 GHz, with newer generations also using 6 GHz in supported regions. A wireless router or access point links nearby devices to one another and often provides a path to the wider internet.
Wi-Fi is based on the IEEE 802.11 family of standards, while Wi-Fi itself is a certification and branding program associated with the Wi-Fi Alliance. The terms are often used interchangeably in everyday conversation, but they are not exactly the same technical designation.
Wi-Fi should not be confused with mobile broadband, Bluetooth, or NFC. Those technologies also use radio, but they serve different purposes, ranges, and networking models. Actual performance depends on interference, distance, channel width, hardware, and network traffic.