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 YouTube has made live events a strategic priority, with its multi-billion dollar bet on Sunday Ticket a big part of that, but Rivera frames it as a larger flywheel at play. Alex Weprin, The Hollywood Reporter, 4 Apr. 2024 Iger has never been afraid to take bold leaps to expand the flywheel, with masterstrokes such as Disney’s new $1.5 billion investment in video game maker Epic Games. Jeffrey Sonnenfeld, Fortune, 2 Apr. 2024 Demographics is the spark finally kicking this flywheel into high gear. Kevin O'Marah, Forbes, 22 Feb. 2024 When needed, the motors could draw power from the flywheel, deploying it in short bursts of up to 8 seconds. Jonathan M. Gitlin, Ars Technica, 16 Oct. 2023 There was no SoulCycle, there was no orange theory, there was no flywheel, there was no Barre, there was nothing. Jane Thier, Fortune, 28 Mar. 2024 Different components of the flywheel play different roles for us. Nick Statt, The Verge, 26 Feb. 2024 The compounding expertise of millions more experienced builders creates ever-faster feedback loops, kickstarts a talent and business flywheel effect, and leads to more inclusive and inventive startup ecosystems. Martin Mignot, Fortune, 18 Mar. 2024 That combined with opening its first store in hometown Encinitas, CA got the brand’s flywheel humming. Pamela N. Danziger, Forbes, 25 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'flywheel.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1784, in the meaning defined above

Time Traveler
The first known use of flywheel was in 1784

Dictionary Entries Near flywheel

Cite this Entry

“Flywheel.” Dictionary, Merriam-Webster, Accessed 22 May. 2024.

Kids Definition


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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