flywheel

noun fly·wheel \ ˈflī-ˌhwēl , -ˌwēl \

Definition of flywheel

: 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)

See flywheel defined for English-language learners

See flywheel defined for kids

Recent Examples of flywheel from the Web

Amazon’s frugality and high-tech investments in logistics create what analysts call a flywheel of ever-declining prices and delivery times.

— david whelan, chicagotribune.com, "What Amazon & Co. should fix first in our health care system," 27 Mar. 2018
From printing presses to the mechanics of manufacturing, the flywheel fostered our intellect and enabled our industry.

— bailey loosemore, The Courier-Journal, "Everything you want to know about Flywheel Brewing, a craft brewery in Kentucky," 4 Mar. 2018
Clean the Flywheel If your mower sees more than 4 hours of use a week or runs in dusty and dirty conditions, uncover the flywheel at midseason and brush off the fins with an old paintbrush.

— timothy dahl, Popular Mechanics, "How to Get Your Lawn Mower Ready for Spring," 8 Feb. 2018
Pushing it to two-thirds fires up the flywheels and starts the minigun rotation.

— david grossman, Popular Mechanics, "Watch This Nerf-Style Minigun Unleash Hell," 17 Jan. 2018
Amazon’s impact could be like when the Clinton Foundation moved into New York City’s Harlem in 2001, giving a hard push to a flywheel of renewal.

— kevin maney, Newsweek, "Big Tech: Hate Amazon, Apple, Facebook and Google? Get in Line," 6 Nov. 2017
How can this be good for the longevity of the starting components: battery, starter, solenoid, flywheel, etc.?

— ray magliozzi, The Seattle Times, "Start-stop feature is aggravating but good for mileage," 5 Sep. 2017
The flywheel, coupled with wind, hydro and battery power, can handle even the biggest bump in demand from the crane, Scott said.

— michelle theriault boots, Alaska Dispatch News, "Kodiak reaps benefits of renewable energy, with lessons for rural Alaska," 31 May 2016
But at times of low-energy demand, that flywheel can be sped back up again.

— megan geuss, Ars Technica, "Here are humanity’s best ideas on how to store energy," 28 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'flywheel.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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.