Odometer
Part of speech: noun
Definition: An instrument attached to the wheel of a vehicle, to measure the distance traversed. A wheel used by surveyors, which registers distance traversed.
Tachometer
Part of speech: noun
Definition: A device for measuring the revolutions per minute (RPMs) of a revolving shaft, as with the driveshaft of an automobile.A device for measuring or indicating velocity or speed, as of blood, a river, a machine, etc..