Definition of pentrough in English:

pentrough

Pronunciation /ˈpɛntrɒf/

noun

(also pentrow)
historical
  • A trough, channel, or conduit, usually made of wooden boards, for conveying water from a weir, dam, etc., to the top of the wheel in a watermill. Compare "penstock", "pen".

Origin

Late 18th century; earliest use found in Transactions of the Society of Arts. From pen + trough.