What was the name of the first major U.S. stock-market crash day in October 1929?

The first major U.S. stock-market crash day in October 1929 was called Black Thursday.

Black Thursday occurred on October 24, 1929, when heavy selling hit the New York Stock Exchange after a period of extreme speculation. The Dow Jones Industrial Average fell sharply, and trading volume reached a then-record level. Leading bankers attempted to restore confidence by buying prominent stocks, temporarily calming the market.

The respite did not end the collapse. Selling intensified again in the following trading days, especially on Black Monday and Black Tuesday. The crash continued into November and contributed to the economic contraction that became the Great Depression, although historians do not treat the crash alone as its sole cause.

Black Thursday is often confused with Black Tuesday, October 29, the later session widely regarded as the most devastating day of the 1929 crash. Both names belong to the same Wall Street episode.