from The Century Dictionary and Cyclopedia
- n. The large wheel which is keyed upon the same shaft as the lifting-barrel of a crane, and by which the barrel is directly revolved. It is the last one in the train of gearing.
Sorry, no etymologies found.
This chain was passed once round a grooved barrel-wheel under the centre of the engine: so that, when the wheel turned, the locomotive, as it were, dragged itself along the railway.