What does "tachometer" mean?

A device for measuring the revolutions per minute (RPMs) of a revolving shaft, as with the driveshaft of an automobile.

What is a synonym for "tachometer"?

Common synonyms include: tach, anemometer, direction finder, instrument, log, rev counter.

Pronounced //təˈkɒmətə(ɹ)//.

/təˈkɒmətə(ɹ)/ noun

noun ·Rare ·Advanced level

Noun

1
A device for measuring the revolutions per minute (RPMs) of a revolving shaft, as with the driveshaft of an automobile.
2
measuring instrument for indicating speed of rotation wordnet
3
A device for measuring or indicating velocity or speed, as of blood, a river, a machine, etc.

From tacho- + -meter.