An instrument on a vehicle's dashboard which indicates the speed of the vehicle when it is running, is called speedometer. The speedometer has the symbol km/h written on its dial.
Odometer is an instrument for measuring the distance travelled by a vehicle. Odometer records the distance travelled by a vehicle in kilometres. We can usually see a small rectangular window within the speedometer dial with the symbol 'km' written on its right side. This gives us the odometer reading for the distance covered by the vehicle.