A beacon is an intentionally conspicuous device
designed to attract attention to a specific location. A classical
example of beacon is the lighthouse, used in navigation, that helps
navigators find their destination.
In electronics, a beacon is a
wireless device (usually called "radio beacon") that
periodically broadcasts a radio signal, that is picked up by one or more
receivers and is used to determine the position of the beacon in the area delimited by the receivers.