Wi-Fi
Wi-Fi is the family of wireless local area networking technologies based on the IEEE 802.11 standards, which lets laptops, phones, televisions and sensors exchange data over radio with a nearby access point, usually a router, that in turn connects them to a wired network and the wider Internet. It is a link-layer technology, the wireless counterpart to Ethernet, and carries ordinary IP traffic.
Wi-Fi is a brand certified by the Wi-Fi Alliance, while the underlying technical standard is IEEE 802.11. The IEEE published the first 802.11 standard in 1997 with data rates of only 1 to 2 megabits per second. Two years later came 802.11b, running at up to 11 megabits per second in the 2.4 GHz band, and 802.11a in the 5 GHz band at up to 54 megabits per second. A trade group, formed in 1999 and now called the Wi-Fi Alliance, tests devices for interoperability and licenses the "Wi-Fi" name, which is why a phone from one maker can join a router from another. A popular belief says the term stands for "wireless fidelity"; it was a marketing coinage and is not an abbreviation of anything.
Wi-Fi shares radio spectrum rather than owning it, so its design is dominated by managing interference and contention. Home Wi-Fi traditionally lives in unlicensed bands near 2.4 GHz and 5 GHz, and newer devices also use 6 GHz where regulators have opened it. Lower frequencies penetrate walls and reach farther but offer fewer clear channels and compete with Bluetooth, cordless phones and microwave ovens; higher frequencies deliver more speed over shorter distances. Unlike Ethernet, a radio cannot reliably listen while it transmits, so Wi-Fi uses collision avoidance (CSMA/CA): a station waits for a quiet channel, backs off a random interval, and expects an acknowledgment for each frame, retransmitting if none arrives. All devices on a channel take turns, so a crowded network or one distant, slow device drags down everyone's throughput.
Generations have been renamed for consumers: Wi-Fi 4 is 802.11n, Wi-Fi 5 is 802.11ac, Wi-Fi 6 is 802.11ax (with Wi-Fi 6E extending it to 6 GHz), and Wi-Fi 7 is 802.11be. Each step combined tricks that squeeze more bits from the same air: wider channels, denser modulation, multiple antennas sending several spatial streams at once (MIMO), and in Wi-Fi 6 techniques such as OFDMA that divide a channel among many devices at the same moment, which matters more in crowded homes and stadiums than raw peak speed. Headline figures quoted on boxes are theoretical link rates under ideal conditions, not what a download will actually achieve.
Wireless traffic can be overheard by anyone in range, so encryption is not optional, and its history is a lesson in getting it wrong. The original WEP scheme was found to be fundamentally breakable, and WPA arrived around 2003 as an emergency replacement, followed by WPA2 in 2004 with AES-based encryption, and WPA3 in 2018 with stronger protection of passwords against offline guessing. An open network with no encryption, such as a cafe hotspot without a password, exposes unencrypted traffic to neighbors, although HTTPS still protects the content of web pages. Hiding the network name, or filtering by MAC address, is a frequent mistaken defense: both are trivially bypassed and provide no real security.
The biggest everyday pitfall is confusing Wi-Fi with the Internet. Wi-Fi is only the last wireless hop between a device and a router; a strong signal with the wrong gateway, a failed DNS server or a saturated broadband line still yields "connected, no Internet." Speed complaints usually come from distance, walls, channel congestion or the broadband plan, not from the radio standard. For latency-sensitive work such as video calls, game streaming or moving large datasets for machine learning, a wired Ethernet connection remains steadier, because it has no radio interference or airtime sharing.
Read Wi-Fi as Ethernet without the wire: an IEEE 802.11 radio link, branded and certified by the Wi-Fi Alliance, that shares unlicensed airwaves politely among many devices and relies on WPA encryption to make an inherently overheard medium safe enough for everyday life.