semicentennial

American  

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

adjective

1. of or relating to a fiftieth anniversary.

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noun

1. a fiftieth anniversary.

2. the celebration of this anniversary.

semicentennial British  

/ ˌsɛmɪsɛnˈtɛnɪəl /

adjective

1. (prenominal) of or relating to the 50th anniversary of some event

2. occurring once every 50 years

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noun

1. a 50th anniversary

Etymology

Origin of semicentennial

First recorded in 1855–60; semi- + centennial

Example Sentences

City University marks its semicentennial with 63,000 alumni.

From Seattle Times • Aug. 8, 2023

To mark the 50th anniversary of saving Pike Place Market, the Market’s traditional fall festival will transform into a semicentennial celebration of the landmark 1971 initiative.

From Seattle Times • Oct. 19, 2021

This season, Wolf Trap in Vienna, Va., returns to the scene to celebrate the semicentennial of the Filene Center.

From Washington Post • Jun. 8, 2021

Northfield being needy and this its semicentennial year, there is now in progress a drive for $3,000,000 to increase faculty pay, provide a teacher-retirement fund, secure upkeep for the physical property.

From Time Magazine Archive

In the twentieth century, the Pioneer was displayed at the Louisiana Purchase Exposition, St. Louis, Missouri, in 1904, and at the Wheeling, West Virginia, semicentennial in 1913.

From The 'Pioneer': Light Passenger Locomotive of 1851 United States Bulletin 240, Contributions from the Museum of History and Technology, paper 42, 1964 by White, John H.