ta·​chom·​e·​ter | \ta-ˈkä-mə-tər, tə-\

Definition of tachometer 

: a device for indicating speed of rotation

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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

Ahead of you, the main instrument display is a pair of physical analog gauges (tachometer on the left, speedometer on the right) with a small multifunction display in between. Jonathan M. Gitlin, Ars Technica, "The Nissan Rogue is a huge sales success, but is it any good? A review," 18 Apr. 2018 An analog tachometer and temperature gauge are to the left, while the right dial shows battery, temperature, and fuel. Eric Bangeman, Ars Technica, "Review: Buick aims high, falls short with $60,000 Enclave Avenir," 2 Mar. 2018 The analog tachometer is flanked by two 7-inch screens. Robert Duffer, chicagotribune.com, "2017 Porsche Panamera is quick and nice for a steep steep price," 18 Sep. 2017 The energy meter in the tachometer, delineated by a drop icon for gas and a bolt icon for electric, is really the only way to sense the subtle shift of energy sources. Robert Duffer, chicagotribune.com, "Volvo surges ahead of competition with XC60 plug-in hybrid," 6 Dec. 2017 With a toggle of the steering wheel control, the tachometer becomes a 7-inch space to roll through audio or phone commands, view nav directions, or check active fuel economy or trip meters. Robert Duffer, chicagotribune.com, "Believe the hype: 2018 Honda Accord is that good," 25 Jan. 2018 The large tachometer indicates a 6,500 rpm redline while the speedometer is marked to an overly optimistic 160 mph. Jeff Yip, Houston Chronicle, "VW’s revamped 2019 Jetta R-Line delivers bang for the buck," 5 May 2018 In front of you is the main instrument display—analog physical dials for the speedometer (left) and tachometer (center), plus a small, also circular, multifunction display on the right. Jonathan M. Gitlin, Ars Technica, "Like a hot hatch on steroids: The Porsche Macan GTS reviewed," 6 Mar. 2018 The instrument panel has an analog tachometer and speedometer bracketing another HD display that can be customized to show the usual bits of data—mileage, radio, navigation, etc. Eric Bangeman, Ars Technica, "Review: Step aside, minivan haters—the Chrysler Pacifica is awesome," 8 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'tachometer.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of tachometer

1810, in the meaning defined above

History and Etymology for tachometer

Greek tachos speed + English -meter

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Time Traveler for tachometer

The first known use of tachometer was in 1810

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English Language Learners Definition of tachometer

: a device that measures how fast something (such as a wheel) is turning

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