to visit a person or place for a short time, usually when you are going somewhere else

I stopped in at work on the way home to check my mail. 我回家的路上顺便去办公室收了一下邮件。

to stay at home, especially in the evening

I've had my tea and I'm stopping in now. 我已经喝过茶了，现在打算呆在家里不出去了。