tachometer

noun

ta·​chom·​e·​ter ta-ˈkä-mə-tər 

tə-

: a device for indicating speed of rotation

Did you know?

A tachometer is literally a "speed-measurer", since the Greek root tach- means "speed". This is clear in the names of the tachyon, a particle of matter that travels faster than the speed of light (if it actually exists, it's so fast that it's impossible to see with any instrument), and tachycardia, a medical condition in which the heart races uncontrollably. Since the speed that an auto tachometer measures is speed of rotation of the crankshaft, the numbers it reports are revolutions per minute, or rpm's.

Examples of tachometer in a Sentence

Recent Examples on the Web

Other new features include an easy-to-read, 7-inch digital instrument display with digital tachometer on the left and a physical speedometer on the right. —Jason Fields, Newsweek, 5 Dec. 2024

That’s not to mention the stunning bi-modal exhaust note, which starts as a deep grumble then swells into a growing cacophony higher up into the tachometer. —Michael Van Runkle, Robb Report, 2 Nov. 2024

Alfa spotters will easily distinguish the 1750 and 2000 GTVs by their four headlamps and the interior’s larger twin tachometer and speedometer. —Robert Ross, Robb Report, 11 Oct. 2024

But edge deeper into the throttle and that small block wakes up, clearly preferring the higher end of the tachometer. —Michael Van Runkle, Robb Report, 18 Sep. 2024

Word History

Etymology

Greek tachos speed + English -meter

First Known Use

1810, in the meaning defined above

Kids Definition

tachometer

noun

ta·​chom·​e·​ter ta-ˈkäm-ət-ər 

tə-

: a device for indicating speed of rotation

Etymology

from Greek tachos "speed" and English meter "an instrument for measuring"