beacon
A BLE device that only advertises, never connects, broadcasting an ID or a reading.
A beacon is a broadcast-only advertiser (iBeacon, Eddystone, or a custom sensor payload) read by any scanner without a connection.
Examples
A beacon uses
ADV_NONCONN_IND: it broadcasts an ID or a reading and never accepts a connection.A sensor that just broadcasts temperature in its 31-byte payload lets a hundred phones read it at once.
See also