Wi-Fi – sometimes written WiFi or even wifi – is a local area network that uses high frequency radio signals to transmit and receive data over distances of 100 metres or so; it uses the Ethernet protocol. Wi-Fi allows an electronic device to use computer networks wirelessly and uses frequencies of 2.4 GHz and 5 GHz.
Based on a quick Google search, it appears that most official sites use the terms WiFi or Wi-Fi interchangeably. With so much variation, wifi is a reasonable variation of Wi-Fi and most users understand the forms wifi, WiFi, Wi-Fi, and possibly even Wifi.
The key to its use is that we are aiming towards being understood, not necessarily maintaining a trademark. If we wanted to maintaine trademarks, we wouldn’t use the generic term Blackberries instead of Blackberry mobile devices.
You should be aware that Wi-Fi is rarely used outside English-speaking areas: most countries refer to it as WLAN (Wireless Local Area Network). In German, the term WLAN is used exclusively and, in an English language context in continental Europe, there is a strong tendency towards using WLAN.
Wi-Fi is the wireless equivalent to the wired Ethernet network, the most common local area network (LAN) technology used in organisations and homes worldwide.
A Wi-Fi logo from the Wi-Fi Alliance certifies that network devices comply with the IEEE 802.11 standard. The Wi-Fi Alliance® is a global, non-profit, industry association. Its members are a worldwide network of companies that bring you the trademark Wi-Fi®.
From 2000 onwards, the Wi-Fi CERTIFIED™ seal of approval has designated products with proven interoperability, industry-standard security protection and the latest technology. The Wi-Fi Alliance has certified more than 23,000 products, delivering a consistent user experience and encouraging the expanding use of Wi-Fi products and services in new and established markets.
Today, billions of Wi-Fi products carry a significant portion of the world’s data traffic in an ever-expanding variety of applications. Wi-Fi is in 25 percent of homes around the world and about two billion Wi-Fi devices were sold in 2013. Wi-Fi adoption continues to grow and the widely-shared vision of connecting everyone and everything everywhere continues.
About 600 Wi-Fi Alliance member companies, from dozens of countries, are part of the organisation, driving new technologies and applications and certifying thousands of Wi-Fi products each year.