EMZETT.Wi-Fi (WLAN)
In short: Wireless LAN — a local network that connects devices via radio instead of cable, usually according to the IEEE 802.11 standard (known as Wi-Fi).
In more detail: An access point broadcasts a radio network to which devices connect with a Wi-Fi password (usually WPA2/WPA3-encrypted). Range and speed depend heavily on the frequency band (2.4 GHz vs. 5 GHz) and obstacles.
In Depth
In so-called infrastructure mode, Wi-Fi mostly runs via a central access point to which all client devices connect (the usual setup at home/in the office) — alternatively there’s also an ad-hoc mode, in which devices connect directly without a central access point, which is rarely used today. The access point regularly sends a beacon signal with the network name (SSID) so that devices within range can find the network and connect.
In terms of security, there have been several generations of encryption standards over the years: WEP (early, now considered insecure and easy to crack), WPA, WPA2 (the de facto standard for a long time) and WPA3 (current, with more robust encryption methods and better protection against brute-force attacks on the Wi-Fi password). Compared with 2.4 GHz, the 5 GHz band offers more usable channels and higher speeds, but penetrates walls less well — modern routers therefore usually transmit on both bands at the same time and automatically choose the more suitable one for each device.