The 1976 United States anniversary was called the bicentennial, in contrast with the America250 semiquincentennial.
A bicentennial commemorates 200 years. The 1976 celebration marked two centuries since the Declaration of Independence was adopted in 1776. America250 marked 250 years, making it a semiquincentennial rather than another bicentennial.
The two anniversaries are separated by 50 years. Both were national commemorations tied to the founding era and Independence Day, but they belonged to different generations and used different public programs, symbols, and events. The 1976 celebration became especially associated with the American Revolution’s historical legacy and the country’s 200-year milestone.
Other anniversary terms follow similar numerical patterns. A centennial is 100 years, a sesquicentennial is 150 years, and a tricentennial is 300 years. Knowing these distinctions prevents the common mistake of calling every major national anniversary a bicentennial.