jubilee
/ˈdʒʊbɪliː/noun
1- a special anniversary of an event, especially one celebrating twenty-five or fifty years of a reign or activity（尤指庆祝25周年或50周年的）周年纪念：
as modifier jubilee celebrations.50周年纪念庆典。
1.1
- Jewish History a year of emancipation and restoration, kept every fifty years【犹太史】五十年节, 禧年（每隔50年一次的圣年, 该年奴隶获释、抵押的土地归还原主）。
1.2
- a period of remission from the penal consequences of sin, granted by the Roman Catholic Church under certain conditions for a year, usually at intervals of twenty-five years（罗马天主教会特许、通常每25年一次、对罪孽免予处罚的）大赦年。
词源
late Middle English: from Old French jubile, from late Latin jubilaeus （annus） '(year) of jubilee', based on Hebrew yōḇēl, originally 'ram's-horn trumpet', with which the jubilee year was proclaimed.