tachometer

An instrument used to measure the rotations per minute of a rotating shaft.

An instrument for measuring velocity.

An instrument for measuring the velocity, or indicating changes in the velocity, of a moving body or substance.

An instrument for measuring the velocity of running water in a river or canal, consisting of a wheel with inclined vanes, which is turned by the current. The rotations of the wheel are recorded by clockwork.

An instrument for showing at any moment the speed of a revolving shaft, consisting of a delicate revolving conical pendulum which is driven by the shaft, and the action of which by change of speed moves a pointer which indicates the speed on a graduated dial.

An instrument for measuring the velocity of the blood; a hæmatachometer.

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.

measuring instrument for indicating speed of rotation