What term does the United States Semiquincentennial use for a 250th anniversary?

The United States Semiquincentennial uses the term semiquincentennial for a 250th anniversary.

The word combines Latin-derived elements meaning half of 500: semi- means half, while quincentennial refers to 500 years. It describes the anniversary as halfway from a 200th anniversary to a 300th anniversary, although the construction is less familiar than bicentennial.

The 2026 commemoration marks 250 years since the Declaration of Independence. Other names have appeared in public discussion, including sestercentennial, bisesquicentennial, and quarter millennium. Semiquincentennial is the name used in the official national commemoration and its organizing commission.

A common mix-up is calling the event a bicentennial. Bicentennial means 200 years, so the United States celebrated that milestone in 1976, not 2026. The 250th anniversary is therefore the semiquincentennial.