flywheel

noun

fly·​wheel ˈflī-ˌ(h)wēl 

: 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)

Did you know?

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

Not a series of one-off bets, but a flywheel that compounds over time. — Daren Smith, IndieWire, 27 May 2026

The flywheel does not need to be replaced every 3-5 years and can be installed outdoors, freeing up more space and cash for compute. — Ameya Paleja, Interesting Engineering, 3 July 2026

The Legacy Mosaic As a byproduct of a forward-looking technology footprint, neobanks leverage clean-slate tech footprints, allowing agentic AI to become an immediate innovation flywheel. — Barney Krishnan, Forbes.com, 1 July 2026

That future will include tech giants with flywheels turning faster than ever, media companies like Fox, Disney and Warner-Paramount scaled up to fight, and other players like NBCUniversal figuring out their place in this new world. — Alex Weprin, HollywoodReporter, 24 June 2026

Word History

First Known Use

1784, in the meaning defined above

Rhymes for flywheel

• abele
• alkyl
• anneal
• appeal
• cartwheel
• conceal
• congeal
• coquille
• corneal
• cornmeal
• genteel
• handwheel

Kids Definition

flywheel

noun

fly·​wheel -ˌhwēl  -ˌwēl 

: a heavy wheel for regulating the speed of machinery