D defs.my
Entry 1 sense Webster, 1913

flywheel

· IPA /flˈaɪwˌiːl/
01 n. A heavy wheel or disk which stores kinetic energy by rotating on a shaft, and by its momentum smoothes the operation of a reciprocating eng…
  1. 1.
    A heavy wheel or disk which stores kinetic energy by rotating on a shaft, and by its momentum smoothes the operation of a reciprocating engine by reducing fluctuations of speed. It is used in certain types of machinery, such as automobiles.