What is the definition of telemetry?

The word 'telemetry' literally translates to 'measuring at a distance,' derived from the Greek words 'tele' (distant) and 'metron' (measure). In the context of amateur radio, it refers specifically to the one-way transmission of data or measurements from a remote sensor back to a receiving station. Common examples of amateur telemetry include a high-altitude weather balloon transmitting its GPS coordinates and temperature, or an amateur satellite beaming down its battery voltage and solar panel status. The distractor describing a 'transmission that initiates, modifies, or terminates the functions of a device' is the exact definition of a 'telecommand,' not telemetry. Other distractors incorrectly suggest that telemetry requires two-way transmissions, whereas telemetry is inherently a one-way data stream.