Wi-Fi

In this context a term that is virtually interchangeable with other terms like WLAN and wireless. A type of Local Area Network, in contrast with Personal Area Network technologies like Bluetooth and Zigbee.

Beacon
Wi-Fi Access Points send out beacons, a specific type of frame with specific information in it, periodically (depending on configuration). The receipt of these beacons allows a Wi-Fi chipset to calculate the signal strength of nearby antennas, which allows for fingerprinting.