golden jubilee
noun [ C usually singular ] mainly UK uk/ˌɡəʊl.dən ˈdʒuː.bɪ.liː/ us/ˌɡoʊl.dən ˈdʒuː.bɪ.liː/
（重要事件的）50周年纪念
the day exactly 50 years after an important occasion, or a special event to celebrate this
The local hospital will be celebrating its golden jubilee on Thursday. 当地医院将在星期四庆祝建院50周年。