thill

Etymology

From Middle English thille, thylle, from Old English þille (“board; floorboard; plank; stake; pole”), from Proto-Germanic *þiljǭ (“board; floorboard; deck”), from Proto-Indo-European *tel- (“plank; board”). Cognate with Dutch deel, German Low German Deel (> English deal (“plank”)), German Diele, Swedish tilja, Icelandic þilja. Akin to English theal (“board; plank”). Doublet of deal.

noun

1. One of the two long pieces of wood, extending before a vehicle, between which a horse is hitched; a shaft.
2. (mining) The shallow stratum of underclay that lies under a seam of coal; the bottom of a coal-seam.
   One by one, Janki leading, they crept into the old gallery – a six-foot way with a scant four feet from thill to roof. 1888, Rudyard Kipling, ‘At Twenty-two’, In Black and White, Folio Society, published 2005, page 405