quadranscentennial

plural quadranscentennials

1. The twenty-fifth anniversary of an event or happening.

   It is a year since we marked the twenty-fifth anniversary of the Journal of Sustainable Tourism, noting then that as we “embark upon the next quadranscentennial… we recognise that the 25 years ahead present a new order of challenges confronting sustainable development and sustainable tourism”.

   2017 December 22, James Higham, “Transforming societies and transforming tourism: sustainable tourism in times of change”, in Journal of Sustainable Tourism, volume 26, number 1

   Synonyms: silver jubilee

1. not comparableOccurring every twenty-five years.

   So when I planned a Quadranscentennial Pnyx, the quadranscentennial gives away that I had otherwise learned my lesson not to undertake such ventures, because I would not be prepared to undertake another for 25 years, when I expect to still be teaching at the age of 91.

   2014, Michael Gose, Common Sense: What It Means to Be a Teacher, page 166

2. not comparableOf or related to a twenty-five-year period.