1. R.C. Ch. A year instituted by Boniface VIII in 1300 as a year of remission from the penal consequences of sin, during which plenary indulgence might be obtained by a pilgrimage to Rome, the visiting of certain churches there, the giving of alms, fasting three days, and the performance of other pious works. It was at first appointed to take place every hundred years, but the period was afterwards shortened to fifty, thirty-three, and twenty-five years, and now 'an extraordinary jubilee is granted at any time either to the whole Church or to particular countries or cities, and not necessarily or even usually for a whole year' (Cath. Dict. 1885).
2. The fiftieth anniversary of an event; the celebration of the completion of fifty years of reign, of activity, or continuance in any business, occupation, rank or condition. silver jubilee (after silver wedding), a name for the celebration for the twenty-fifth anniversary; so diamond jubilee, applied to the celebration of the sixtieth year of the reign of Queen Victoria.