a gorge or ravine, esp in North America, usually formed by the down-cutting of a river in a dry area where there is insufficient rainfall to erode the sides of the valley
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
a deep river valley with very steep, often perpendicular, walls and a narrow floor, usually completely occupied by theriverbed. One of the largest canyons in the world is the GrandCanyon of the Colorado River in the USA (length, over 320 km;depth, to 1, 800 m).
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
A chasm, gorge, or ravine cut in the surface of the earth by running water; the sides are steep and form cliffs.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.