Thill

n.	1.	One of the two long pieces of wood, extending before a vehicle, between which a horse is hitched; a shaft.
	2.	(Mining) The floor of a coal mine. Thill coupling a device for connecting the thill of a vehicle to the axle.

Noun

1.

thill - one of two shafts extending from the body of a cart or carriage on either side of the animal that pulls it

shaft