Wi-Fi is a wireless networking technology that uses radio waves to provide wireless high-speed Internet access. A common misconception is that the term Wi-Fi is short for "wireless fidelity," however Wi-Fi is a trademarked phrase that refers to IEEE 802.11x standards.
Wi-Fi originated in Hawaii in 1971, where a wireless UHF packet network called ALOHAnet was used to connect the islands. Later protocols developed in 1991 by NCR and AT&T—called WaveLAN— became the precursor to the IEEE 802.11 standards. Read more here.