The term “semiquincentennial” represents 250 years in the America250 anniversary name.
The word combines “semi,” meaning half, with “quincentennial,” a 500-year anniversary. Half of 500 is 250, so a semiquincentennial is a 250th anniversary. America250 uses the term for the United States’ 250th anniversary of independence in 2026.
The word is less familiar than “centennial” for 100 years or “bicentennial” for 200 years. That unfamiliarity has led writers and event organizers to use simpler descriptions such as “America’s 250th birthday” or “the 250th anniversary of independence.”
Other names appear in reference works, including “sestercentennial,” “quarter millennium,” and “bisesquicentennial.” They describe the same 250-year interval, but “America250” is the most recognizable branding for the 2026 observance.