jubilee

Concise Oxford English Dictionary © 2008 Oxford University Press:
jubilee/ˈʤuːbɪliː/

▶noun

• 1 a special anniversary, especially one celebrating twenty-five or fifty years of something.

• 2 Jewish History a year of emancipation and restoration, kept every fifty years.

• 3 a period of remission from the penal consequences of sin, granted by the Roman Catholic Church under certain conditions for a year, at intervals of twenty-five years.

– origin ME: from OFr. jubile, from late L. jubilaeus (annus) ‘(year) of jubilee’, based on Heb. yōḇēl, orig. ‘ram's-horn trumpet’, with which the jubilee was proclaimed.