an occasion when two or more similar things happen at the same time, especially in a way that is unlikely and surprising

You chose exactly the same wallpaper as us - what a coincidence! 你选的壁纸跟我们的一模一样——真巧！

Is it just a coincidence that the wife of the man who ran the competition won first prize? 赢得头等奖的人是竞赛组织者的老婆，这难道仅仅是巧合吗？

a series of strange/amazing coincidences 一系列奇怪／令人惊讶的巧合

chance or luck

Just by coincidence, I met my old schoolmate again 50 years later. 纯粹是碰巧了，我在50年后又遇到了我的老同学。

[ + that ] It was pure/sheer coincidence that I remembered his phone number. 我记住他的电话号码纯属偶然。

By some strange coincidence, he was passing the house just when it happened. 事情发生时他碰巧路过这所房子。