What is the official anniversary term used for America250, the United States’ 250th birthday?

The official anniversary term used for America250 is semiquincentennial.

The word combines “semi,” meaning half, with “quincentennial,” meaning a 500th anniversary. Together, the term denotes a 250th anniversary, or half of 500 years. It is the formal name used for the United States’ 250th-anniversary observance.

Several other anniversary words are easy to confuse with it. A bicentennial marks 200 years, a sesquicentennial marks 150 years, and a tercentennial marks 300 years. “Quarter millennium” is another understandable description, but it is not the official event name.

America250 is the branding used for the broader national program. The United States Semiquincentennial Commission was created to coordinate and promote commemorations connected with the anniversary of American independence.