Word forms: (regular plural) flywheels
COBUILD Key Words for Automotive Engineeringnoun(Automotive engineering: Vehicle components, Engine, transmission, and exhaust) A flywheel is a heavy wheel that is part of some engines. It regulates the engine's rotation, making it operate at a steady speed. ⇒ A flywheel stores energy as it spins inside a casing. ⇒ A flywheel that keeps an engine turning relies on its momentum to keep going. ⇒ To function, the starter pushes a toothed gear so that it meshes with the flywheel in order to turn the engine over.