Noun

(en noun)

An elongated depression between hills or mountains, often with a river flowing through it.

* {{quote-magazine, date=2013-08-16, author= John Vidal

, volume=189, issue=10, page=8, magazine=(The Guardian Weekly) , title= Dams endanger ecology of Himalayas , passage=Most of the Himalayan rivers have been relatively untouched by dams near their sources. Now the two great Asian powers, India and China, are rushing to harness them as they cut through some of the world's deepest valleys .}}

The area which drains into a river.

Any structure resembling one, e.g., the meeting point of two pitched roofs.

The internal angle formed by the intersection of two sloping roof planes.