What term names the United States' 250th anniversary celebration in America250 materials?

The term for the United States' 250th anniversary celebration in America250 materials is semiquincentennial.

A semiquincentennial is a 250th anniversary. The word combines “semi,” meaning half, with “quincentennial,” relating to 500 years. Half of 500 is 250, giving the term its literal meaning.

The name is less familiar than “centennial,” which means 100 years, or “bicentennial,” which means 200 years. It is also sometimes called a bisequicentennial or quarter-millennium anniversary, but semiquincentennial is the standard term used for the United States' 250th anniversary in the relevant commemoration context.

The anniversary is based on the adoption of the Declaration of Independence on July 4, 1776. That makes July 4, 2026, the 250th anniversary date. Earlier national commemorations included the 1876 Centennial Exposition, the 1926 sesquicentennial observance, and the nationwide bicentennial celebrations of 1976.