Definify.com
Webster 1913 Edition
Balance wheel
Bal′ance wheelˊ
.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).
2.
(Mach.)
A wheel which imparts regularity to the movements of any engine or machine; a fly wheel.