to build a fence around an area

She would need to fence in the field if she wants to keep a horse there. 如果她打算在那儿养一匹马，就必须把那块地用栅栏围起来。

to limit someone's activity in a way that annoys them or makes them unhappy

I feel fenced in by all the rules and regulations at work. 我觉得工作上的条条框框束缚住了我的手脚。