It is trademarked name associated with wireless technology and it’s not an abbreviation.
It doesn’t mean wireless fidelity.
Most of us use Wi-Fi every day. If you were to ask 10 people what it stands for, 9 people would probably say “wireless fidelity” because wi-fi sounds like hi-fi, which means “high fidelity”.
In fact, Wi-Fi does not mean wireless fidelity.
It is actually a proper noun – hence the capitalization. It is a registered trademark of the Wi-Fi Alliance.
Phil Belanger, a founding member of the Wi-Fi Alliance who presided over the selection of the name “Wi-Fi” writes:
Wi-Fi doesn’t stand for anything.
It is not an acronym. There is no meaning.
Wi-Fi and the ying yang style logo were invented by Interbrand.
We … hired Interbrand to come up with the name and logo that we could use for our interoperability seal and marketing efforts. We needed something that was a little catchier than “IEEE 802.11b Direct Sequence”.
In the early days, the Wi-Fi Alliance did use a tagline that suggested the connection to wireless fidelity – “The Standard for Wireless Fidelity” but after about a year they stopped using the tagline. Belanger explains “We were dumb to confuse and water down their efforts by adding the meaningless tag line. Please help reinforce the good work that we did and forget the tag line.”