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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
Michael Teo Van Runkle, Forbes.com, 1 July 2025
The latter offers a layout featuring a prominent round tachometer in the center of the cluster flanked by customizable displays for the engine’s effort, suspension settings and other monitoring.
—James Raia, Mercury News, 2 June 2025
That means your maps, music, messages, speedometer, tachometer, and even tire pressure all live in one seamless interface.
—Paul Lamkin, Forbes.com, 16 May 2025
The instrument cluster features throwback green digits on the tachometer, accents mirrored on the Sport Chrono stopwatch (on that note, the automaker has created a high-quality chronograph exclusively offered for buyers of the 911 Spirit 70.
—Michael Harley, Forbes.com, 23 Apr. 2025
See All Example Sentences for tachometer
Cite this Entry
“Tachometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/tachometer. Accessed 19 Jul. 2025.
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tachometer
noun
from Greek tachos "speed" and English meter "an instrument for measuring"
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