semiquincentennial

American  

[sem-ee-kwin-sen-ten-ee-uhl, sem-ahy-] / ˌsɛm iˌkwɪn sɛnˈtɛn i əl, ˌsɛm aɪ- /

noun

1. a 250th anniversary or its celebration.

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adjective

1. relating to a 250th anniversary or its celebration.

2. lasting or having lasted 250 years; 250 years old.

Explanation

Semiquincentennial is a very long word for a very big anniversary — 2026 is the semiquincentennial, or 250th anniversary, of the United States. Semiquincentennial derives from the Latin words semi, "half," quinque, "five," and centum, "one hundred." You don't need this word very often, since it's rare that a country, building, or organization marks its 250th anniversary, but when you do, it's a big deal. The British Parliament celebrated its semiquincentennial in 1957, and the Taj Mahal was built in 1648, which means its semiquincentennial happened back in 1898.

Example Sentences

UFC Freedom 250, they called it, in recognition of the approaching semiquincentennial.

From The Wall Street Journal • Jun. 15, 2026

It’s a fitting emblem of what’s to come in a long-planned show curated to coincide with the country’s upcoming semiquincentennial, and crafted to pose land itself as central to the country’s complex past.

From Los Angeles Times • Jun. 10, 2026

Half the documentary’s parenthetical title — “The Weight of the World” — speaks to a common leaden feeling of gloom hovering over America’s semiquincentennial summer.

From Salon • Jun. 7, 2026

These exhibits and others that present some highlights of America's faltering progress toward a perfect union go on show for two months in Washington next Tuesday ahead of the semiquincentennial.

From Barron's • May 29, 2026

The long-running show’s semiquincentennial special flashes back to particularly wonderful American works that have appeared on it over the past 25 years.

From The Wall Street Journal • Apr. 16, 2026