flywheel

American  

[flahy-hweel, -weel] / ˈflaɪˌʰwil, -ˌwil /

noun

Machinery.

1. a heavy disk or wheel rotating on a shaft so that its momentum gives almost uniform rotational speed to the shaft and to all connected machinery.

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flywheel British  

/ ˈflaɪˌwiːl /

noun

1. a heavy wheel that stores kinetic energy and smooths the operation of a reciprocating engine by maintaining a constant speed of rotation over the whole cycle

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Etymology

Origin of flywheel

First recorded in 1775–85; fly ² + wheel

Example Sentences

Whilst these devices are designed for longer term space missions, the recent Artemis II mission around the moon took a specially developed exercise device called the flywheel.

From BBC • May 22, 2026

It shows that the whole company is built on a powerful flywheel: SpaceX rockets launch Starlink satellites, and those Starlink satellites are the reason SpaceX can launch more rockets.

From The Wall Street Journal • May 22, 2026

“Earlier this year, investors worried hyperscalers were building too much AI infrastructure, too quickly, with capex rising sharply and the revenue flywheel still unclear.”

From Barron's • Apr. 27, 2026

“Neo reinforces Apple’s flywheel effect by bringing more price-sensitive consumers into the Mac ecosystem, deepening cross-device engagement through iPhone integration features like Handoff that could ultimately drive incremental hardware and services monetization,” Daryanani wrote.

From Barron's • Mar. 4, 2026

The starter cord was a three-foot length of rope that wrapped tightly around the engine’s flywheel.

From "Flush" by Carl Hiaasen