Oxford Dictionary English diamond jubilee nounnoun BrE BrE//ˌdaɪəmənd ˈdʒuːbɪliː// ; NAmE NAmE//ˌdaɪəmənd ˈdʒuːbɪliː// [usually singular] Add to my wordlistjump to other resultsthe 60th anniversary of an important event, especially of somebody becoming king/queen; a celebration of this event Queen Victoria had been on the throne for 60 years and her diamond jubilee was being celebrated. compare golden jubilee, silver jubileeCheck pronunciation: diamond jubilee oxfordlearnersdictionaries.com