Meaning:

This is short from “黑色星期五,” translated from the English term “Black Friday.” Black Friday is an informal name for the Friday following Thanksgiving Day in the United States, which is celebrated on the fourth Thursday of November. The day after Thanksgiving has been regarded as the beginning of the Christmas shopping season since 1952, although the term “Black Friday” didn’t become widely used until more recent decades. Many non-retail employees and schools have both Thanksgiving and the following Friday off, which, along with the following regular weekend, makes it a four-day weekend, thereby increasing the number of potential shoppers.

Example:

A: 今年黑五你上亚马逊海淘了吗？

Jīnnián hēiwǔ nǐ shàng yàmǎxùn hǎitáo le ma？

Did you buy anything during the Black Friday sales on Amazon?

B: 没有，双十一已经把我的口袋掏空了。

Méiyǒu，shuāngshíyī yǐjīng bǎ wǒ de kǒudài tāo kōng le。

Not really. The Single’s Day sales already burned a hole in my pocket.