Thill coupling

Thill Thill, n. [OE. thille, AS. ?ille a board, plank, beam, thill; akin to ?el a plank, D. deel a plank, floor, G. diele, OHG. dili, dilla, Icel. ?ilja a plank, planking, a thwart, ?ili a wainscot, plank; cf. Skr. tala a level surface. [root]236. Cf. {Fill} a thill, {Deal} a plank.] 1. One of the two long pieces of wood, extending before a vehicle, between which a horse is hitched; a shaft. [1913 Webster]

2. (Mining) The floor of a coal mine. --Raymond. [1913 Webster]

{Thill coupling}, a device for connecting the thill of a vehicle to the axle. [1913 Webster]