n.

1. 事故；災禍[C]
   He died in an automobile accident years ago.

   他數年前死於車禍。

2. 意外事情；偶然因素，機遇[C][U]
   The discovery was a happy accident.

   這一發現出人意料，令人高興。

n.

1. an unfortunate incident that happens unexpectedly and unintentionally.
2. something that happens by chance or without apparent cause.
   ▸chance:

   we met by accident.
3. Philosophy  a property of a thing which is not essential to its nature.