not in or at the centre or main part of something 旁边的，在边上的
We parked the car on a side street/road (= a small road, especially one that joins on to a main road).
我把汽车停在小道上。
I think that’s a side issue (= a subject which is separate from the main one) which we should talk about later.
我认为这是个次要问题，我们应该以后再讨论。
I’d like a side dish of potatoes (= some potatoes on a separate plate).
我想要盘土豆作为配菜。