What adjective describes the 250th anniversary commemorated by America250?

America250 commemorates the United States semiquincentennial, the 250th anniversary of American independence.

The word combines “semi,” meaning half, with “quincentennial,” meaning a 500th anniversary. Together, the term describes half of five centuries, or 250 years. It is also sometimes called a sestercentennial, bisesquicentennial, or quarter millennium, but “semiquincentennial” is the formal term used for the national commemoration.

The anniversary centers on July 4, 2026, marking 250 years since the Continental Congress adopted the Declaration of Independence in 1776. America250 is the branding used by the congressional commission organizing and promoting the observance.

The term can be confused with “sesquicentennial,” which means 150th anniversary, and “bicentennial,” which means 200th anniversary. The next major U.S. anniversary in this naming sequence will be the tricentennial in 2076.