flywheel

noun

fly·​wheel ˈflī-ˌ(h)wēl How to pronounce flywheel (audio)
: a heavy wheel for opposing and moderating by its inertia any fluctuation of speed in the machinery with which it revolves
also : a similar wheel used for storing kinetic energy (as for motive power)

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A heavy wheel attached to a rotating shaft, a flywheel smooths out delivery of power from a motor to a machine. The inertia of the flywheel moderates fluctuations in the speed of the engine and stores the excess energy for intermittent use. In automobile engines, the flywheel smooths out the pulses of energy provided by combustion in the cylinders, and provides energy for the compression stroke of the pistons. In power presses, the punching, shearing, and forming are done in a fraction of the operating cycle. During the rest of the cycle, the speed of the flywheel is built up by a comparatively low-powered motor, and most of the required energy for the cycle is provided by the flywheel.

Examples of flywheel in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
No stopping the Product Commerce flywheel in Korea. ... Michael Bloom, CNBC, 5 July 2025 Whoever cracks this first could use a first mover’s advantage to build a hard-to-beat flywheel of highly engaged, big-spending consumers that attracts partner brands and retailers that don’t want to miss out on a new growth channel. Jason Del Rey, Fortune, 25 June 2025 The flywheel effect is also - and perhaps mainly - driven by those who spend time working for one or more technology startups before launching their own ventures. Trevor Clawson, Forbes.com, 14 June 2025 This can certainly help teams meet the flywheel of demand, but administrative processes also need to be addressed. Megan Poinski, Forbes.com, 18 June 2025 See All Example Sentences for flywheel

Word History

First Known Use

1784, in the meaning defined above

Time Traveler
The first known use of flywheel was in 1784

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Cite this Entry

“Flywheel.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/flywheel. Accessed 11 Jul. 2025.

Kids Definition

flywheel

noun
fly·​wheel -ˌhwēl How to pronounce flywheel (audio) -ˌwēl How to pronounce flywheel (audio)
: a heavy wheel for regulating the speed of machinery

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