n.

1. 降雨，下雨；降雨量[U][C]
   There was another rainfall early this morning.

   今天清晨又下了一場雨。

   What is the average annual rainfall in this region?

   這個地區的年平均降雨量是多少？

n.

1. the fall of rain.
2. the quantity of rain falling within a given area in a given time.