ghyll

/ɡɪl/
noun
  1. A narrow, steep-sided valley, often with a stream running through it; a ravine or gorge.
    • A cool breeze came up from the ghyll, carrying the sound of rushing water.
    • We hiked down into the ghyll, where the waterfall echoed off the rocky walls.
    • The old map marked several ghylls in the Lake District, popular with climbers.