From Longman Dictionary of Contemporary Englishsilver jubileeˌsilver ˈjubilee noun [countable] especially British English TMCCELEBRATEthe date that is exactly 25 years after the date when something important happened, especially when someone became king or queen the Queen’s Silver Jubilee
Examples from the Corpus
silver jubilee• On October 10,1986, the silver jubilee of the parish was celebrated.• The 73-year-old Bishop was ordained in February, 1969, shortly before the silver jubilee of his becoming a priest.• A representation of this picture was incorporated in the 1984 design, the silver jubilee of well-dressing in Dore.• Bernard Woods at the conclusion of the concelebrated Mass to mark the silver jubilee of his ordination. 