What was the worldwide stock-market crash on October 28 and 29, 1929 collectively called?

The worldwide stock-market crash on October 28 and 29, 1929, was the Wall Street Crash of 1929.

The New York market had risen dramatically during the 1920s, with widespread margin buying and speculation. When confidence weakened, investors rushed to sell. The Dow Jones Industrial Average fell 12.82% on Black Monday, October 28, and 11.73% on Black Tuesday, October 29.

The crash did not by itself cause every feature of the Great Depression. Banking failures, falling demand, deflation, international debt problems, and policy mistakes deepened the economic contraction that followed. Nevertheless, the crash became its most famous financial symbol.

Black Tuesday is one date within the broader Wall Street Crash of 1929. The terms are related but not identical: the crash covers the wider market collapse, while Black Tuesday specifically identifies October 29.