Definition of "flywheel" []

• A heavy-rimmed rotating wheel used to minimize variations in angular velocity and revolutions per minute, as in a machine subject to fluctuation in drive and load. (noun)
• An analogous device, especially one used to regulate the speed of clockwork. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "A CVT-controlled flywheel is particularly suited to stop-start driving situations when real-world fuel economy is often at its worst."
• "Kinetic Traction Systems Inc. is a provider of so-called flywheel power for rail systems."
• "Near the flywheel was the maker badge, a repeat of the design on the glass cover, but here the stars were inlaid with small diamond-cut rubies, and the lightning bolts were coated with alternating layers of gold and silver."