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n. A machine that records the measurements of a tachometer, especially one in a vehicle recording its speed and the times at which it was driven.

n. A device that records the distance and time traveled by a vehicle (especially a truck or coach), used to check the drivers' working time.

n. A recording or registering tachometer; also, its autographic record.

n. A recording tachometer applied to shafting or wheels to register rotation-speed; a speed-indicator. Also tacheograph.

n. a tachometer that produces a graphical record of its readings; used to record the speed and duration of trips in a motor vehicle

"The new rules forbid drivers of commercial vehicles, including rescue tow trucks, from travelling more than 62 miles from their bases unless the vehicle is fitted with a tachograph – a device that monitors the number of hours spent on the road."

tachometer    tach   

tachometer