Canyon
A deep valley with steep sides would be called a gorge or canyon.
a deep, steep-sided, narrow river valley
A canyon is a deep narrow valley.
Canyon
Canyon
A ravine is a narrow, deep valley with steep sides typically formed by water erosion. It is often characterized by its rugged terrain and lack of vegetation.
A narrow valley is a V-shaped valley, or river valley. A narrow valley has steep sloped sides that look like the letter V. They are formed by a strong stream.
Canyon
A ravine.
A glen or a gorge.
A 'hanging valley' is a valley which is cut across by a river flowing in a deeper valley.
Try "canyon".