Balance wheel (&unr_;). 1. (Horology) (a) A wheel which regulates the beats or pulses of a watch or chronometer, answering to the pendulum of a clock; -- often called simply a balance. (b) A ratchet-shaped scape wheel, which in some watches is acted upon by the axis of the balance wheel proper (in those watches called a balance).
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2. (Mach.) A wheel which imparts regularity to the movements of any engine or machine; a fly wheel.
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