| tachometer | An instrument for measuring the velocity, or indicating changes in the velocity, of a moving body or substance. Specifically: 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. <physiology> An instrument for measuring the velocity of the blood; a haematachometer. Origin: Gr. Swiftness, speed (fr. Quick): cf. F. Tachometre. Source: Websters Dictionary (01 Mar 1998) |
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