n.[C]

1. 边界，分界线[（+between）]
   The river is the boundary between the two countries.

   这条河是两国的分界线。

2. 界限，范围
   With the advance in science, the boundaries of human knowledge are being pushed further out.

   随着科学的发展，人类知识的范围在不断扩大。

n.

1. a line marking the limits of an area.
2. Cricket  a hit crossing the limits of the field, scoring four or six runs.