Telemetry
Telemetry is the live stream of data from the car to the garage — hundreds of channels covering everything from tyre temperature to throttle position.
It is what lets an engineer know a problem before the driver reports it, and it is how two team-mates' laps are compared corner by corner rather than by stopwatch.
The flow is one-way. Teams could once adjust the car remotely; that has been banned for years, so anything that changes on track has to be done by the driver's own hands.