Meaning of escape wheel

escape' wheel"

Pronunciation: [key]
— Horol. Horol.
  1. a toothed wheel for regulating a going train to which it is geared, engaging intermittently with the pallets of a pendulum or balance mechanism in such a way as to cause the mechanism to oscillate rhythmically, and in so doing free the going train for part of each oscillation. Also calledSee diag. under
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.