I don't think there is a term...
You may be looking for the term 'Golden' if thinking of 50 years of marriage, other than that, answer as above
50 years of marriage is known as a "golden wedding anniversary."
Golden jubilee
jubilee
An 150 year celebration is called a Sesquicentennial celebration
It is called a "centennial celebration"
A 100 year celebration is called a centennial celebration.
60 year celebration
An 150 year celebration is called a Sesquicentennial celebration
55th wedding celebration is Emerald.
Centennial
It is called Centenary.
An Emerald anniversary
Diamond Jubilee
It is a century or a centennial
Diamond Jubilee