driving-wheel
a. A wheel which communicates motion to one or more other wheels or machinery. b. Each of the large wheels of a locomotive engine, to which the power is transmitted through the connecting-rod and crank. c. The wheel of a bicycle or tricycle to which the force is directly applied. Also fig.
| 1838 N. Wood Railroads, An engine..with driving wheels ten feet diameter. 1870 Emerson Soc. & Solit. vi. 116 The men in cities who are the centres of energy, the driving-wheels of trade, politics, or practical arts. |