clough

noun4

1. •
   (US, Northern-England) A narrow valley; a cleft in a hillside; a ravine, glen, or gorge.

   • The day-sky glimmered on the dew[…] And lurked in heath and braken clough — 1813
2. •
   (dialect) The cleft or fork of a tree; crotch.

   • The same praise should not be refused to the North-countryman who talks of "the clough" of the tree, literally the valley, the cleft, where the branches part. — 1865
3. •
   A sluice used in returning water to a channel after depositing its sediment on the flooded land.
4. •
   (dialect) A wood; weald.