WiFi stands for Wireless Fidelity. This term was coined by a branding company, and it only caught on in its abbreviated form. It describes a technology for radio wireless local area networking of devices based on the IEEE 802.11 standards, which are maintained by the Institute of Electrical and Electronics Engineers (IEEE) LAN/MAN Standards Committee (IEEE 802).
The first version of the IEEE 802.11 standards was released in 1997, but their origin dates to 1985 and the release of the ISM band for unlicensed use by the U.S. Federal Communications Commission. Today, multiple revisions of the IEEE 802.11 standards are in use, which is possible thanks to the backward compatibility of IEEE 802.11 hardware.