n.[C]

1. 山谷；溪谷
   The road gradually widened until we found ourselves in a large valley.

   路渐渐宽了起来，最后我们走进了一个大的山谷。

2. 流域
   the Yangtze valley

   长江流域

3. 低凹处
4. 【建】屋谷，屋顶排水沟

n.

1. a low area between hills or mountains, typically with a river or stream flowing through it.
2. Architecture  an internal angle formed by the intersecting planes of a roof, or by the slope of a roof and a wall.