from The Century Dictionary and Cyclopedia
- n. A shaft-horse as distinguished from a leader; a wheeler.
Sorry, no etymologies found.
But he had steadied down into a pole-horse who could set an example that was worth more than all the six-foot lashes ever tied to a whip-stock.
It was different in the case of Marengo Todd, driver of the pole-horse, and entitled to "protection."