Wifi means a local area network that uses high frequency radio signals to transmit and receive data over distances of a few hundred feet. It uses ethernet protocol. Full form is Wide Fidelity
4.Direct computer-to-computer communications
HIFI - Equipment for the reproduction of sound with high fidelity to distinguish it from the poorer quality sound produced by inexpensive audio equipment. Ideally, high-fidelity equipment has minimal amounts of noise and distortion and an accurate frequency response. Full forms is High Fidelity.
RCA Victor began recording performances by several orchestras on optical sound around 1941, resulting in higher-fidelity masters for 78-rpm discs.