Happenstance is a chance event: something that happens, with nobody planning it.

Happenstance這個字 is a chance event是一種偶然發生的事：something that happens就是那種發生了的事，with nobody planning it卻沒有人事先計畫。

People often say by happenstance to mean by chance, or by accident, though actually it sounds a little more story-like and old-fashioned than plain by chance. You will hear it more in American English than in everyday British talk.

People often say人們常說 by happenstanceby happenstance to mean意思是 by chance, or by accident「碰巧」或「不小心」，though actually it sounds a little more story-like and old-fashioned than不過其實它聽起來比 plain by chance單純的by chance更像說故事、也更老派一點。You will hear it more in American English than in你會在美式英文裡比 everyday British talk日常英式口語更常聽到它。

It is not a science word. It is a slightly literary way of saying that luck, not a plan, put two things together.

It is not a science word它不是一個科學用語。It is a slightly literary way of saying that它是一種稍微文學一點的說法，說的是 luck, not a plan是運氣、不是計畫，put two things together把兩件事湊在一起。

A meeting in the street can be happenstance; a whole chain of small accidents can be happenstance too.

A meeting in the street在街上偶遇 can be happenstance可以是happenstance；a whole chain of small accidents一連串的小意外 can be happenstance too也可以是happenstance。

Do not hear happy inside it and think of a good mood. The old piece happ meant luck or chance, not a smile.

Do not hear happy inside it不要因為裡面聽起來像happy，and think of a good mood就以為跟好心情有關。The old piece happ古字happ meant luck or chance的意思是運氣或機緣，not a smile不是笑容。