Centenary.
Centennial
It is called a "centennial celebration"
A three-hundred-year celebration is called a tricentennial.
It is called Centenary.
end of the year celebration means its the last day to spend time with this old year, old life and time to start a new year and a new life.
An 150 year celebration is called a Sesquicentennial celebration
Samhain is the celebration of the light half of the year changing to the dark. It is a sort of new year and it was a feasting day. It was also that this "in between time" was the day for spirits and to celebrate and feast for them. Which means Beltane is the celebration from the dark part of the year to the light, and for the harvest.
A 100 year celebration is called a centennial celebration.
"bi" means two and "centi" means hundred and "anual" means year. so bi-centen-nial means "every two hundred years."
60 year celebration
It means that company or thing has been in business or existed for more than a 1000 years.
No, there is only one for a full one hundred year-period, the 'centennial'.
Two hundred year anniversary, but that's not "one word".