Definition of "thill"

thill

/θɪl/

noun
plural thills
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.
  Quotations
  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