Black Friday Definition

noun

The Friday after Thanksgiving, traditionally the beginning of U.S. Christmas shopping and a day of brisk retail sales.

Webster's New World

A Friday falling on the 13th day of the month (therefore doubly ill-omened).

Wiktionary

Any Friday actually darkened by catastrophe.

Wiktionary

The anniversary of a number of catastrophic or unfortunate historical events originally occurring on a Friday.

Wiktionary

pronoun

(US, business, retailing) The day after Thanksgiving Day, generally regarded as the first day of the Christmas season, and the busiest shopping day of the year. (Although this usage may also very possibly originate in Etymology 1)

Wiktionary

By extension, the sales period involving heavy price reductions immediately following U.S. Thanksgiving Day, from Friday (the original Black Friday) through Monday (Cyber Monday).

Wiktionary

Other Word Forms of Black Friday

Noun

Singular:

Black Friday

Plural:

black-fridays

Origin of Black Friday

Because retailers typically post profits ('in the black') rather than losses ('in the red').

From Wiktionary
By ancient superstition Friday is an ill-omened day.

From Wiktionary