Mostly just the 75th anniversary. Although in the older days when they still used more Latin terms, it would have been a Diamond Anniversary and the Latin term would have been Dodranscentennial (a quarter less than a century).
diamond jubilee
Platinum year
Diamond Anniversary
A 75th birthday anniversary is commonly referred to as a "diamond jubilee."
Monopoly celebrated its 75th anniversary in 2010.
What is a 75th anniversary model 1895 lever action savage arms worth
The 150th anniversary of the signing of the Treaty of Waitangi.
Traditionally, 75 wedding anniversaries are celebrated with diamond white. This is because reaching the 75th anniversary is a very rare occurrence.
The Kraft 75th Anniversary Special - 1978 TV was released on: USA: 24 January 1978
Disney 411 - 2004 Mickey's 75th Anniversary was released on: USA: 2 June 2004
The Mummy 75th Anniversary Tribute - 2008 V is rated/received certificates of: USA:PG-13
Donald Tank has written: 'Berthold, ND 75th anniversary' -- subject(s): Berthold, ND 75th anniversary, Genealogy, History, Indexes