- 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 haematachometer.
Tachometer Tachometer is an instrument that tells the driver how fast the engine is rotating, commonly including a redline to indicate the maximum engine