Definition of "canyon"

After we have crossed the Glenderamackin stream, which drains the northern slopes of Saddleback, and the latter has united with the St. John's Beck to form the Greta, however, we see ahead the miniature canyon the Greta has hollowed out for itself, and into the depth of which the train now descends.

1961 October, Voyageur, “The Cockermouth, Keswick & Penrith Railway”, in Trains Illustrated, page 601

Snow filled her mouth. She caromed off things she never saw, tumbling through a cluttered canyon like a steel marble falling through pins in a pachinko machine.

2012, John Branch, “Snow Fall: The Avalanche at Tunnel Creek”, in New York Times‎