What is the official term for the United States’ 250th anniversary?

The official term for the United States’ 250th anniversary is semiquincentennial.

The word combines Latin-derived parts associated with half, five, and hundred, producing the meaning “half of five hundred,” or 250. It is the standard name used for the national anniversary planned for July 4, 2026.

The event is also branded as America250, a shorter public-facing name. Other terms appear in historical and reference sources, including sestercentennial, bisesquicentennial, and quarter millennium, but semiquincentennial is the principal modern term for the United States celebration.

The naming pattern can be compared with more familiar anniversary words. A centennial marks 100 years, a bicentennial marks 200 years, a sesquicentennial marks 150 years, and a tricentennial marks 300 years. The 250th anniversary therefore needs a less familiar word than the milestone celebrations that came before it.