tachometer
noun/təˈkɒmətə(ɹ)/
Etymology From tacho- + -meter.
1
A device for measuring the revolutions per minute (RPMs) of a revolving shaft, as with the driveshaft of an automobile.
2
A device for measuring or indicating velocity or speed, as of blood, a river, a machine, etc.
- Synonyms
- rev counter, tach
- Derived terms
- cardiotachometer, haematachometer, phototachometer, pneumotachometer
- Related terms
- tachygraphy, tachymeter
- Coordinate terms
- speedometer, tachograph