What term describes America's 250th anniversary, America250?

America's 250th anniversary, America250, is called the United States Semiquincentennial.

The word combines “semi,” meaning half, with “quincentennial,” a 500th anniversary. Together, the term identifies a 250-year anniversary. It is the formal historical label used for the celebration of the United States’ independence anniversary in 2026.

Several alternative terms have appeared, including bisesquicentennial, sestercentennial and quarter millennium. These are understandable, but semiquincentennial is the term most closely associated with the official national commemoration. The shorter brand name America250 is used extensively in public-facing programs.

The naming can cause confusion because other anniversary words are more familiar. A bicentennial is 200 years, a sesquicentennial is 150 years and a tricentennial is 300 years. America’s 250th anniversary therefore needs its own less common term.