The Merriam-Webster dictionary defines Jubilee
1 - a year of emancipation and restoration provided by ancient Hebrew law to be kept every 50 years by the emancipation of Hebrew slaves, restoration of alienated lands to their former owners, and omission of all cultivation of the land.
2 - a religious song of black Americans usually referring to a time of future happiness.
The Hebrew usage is said to be based on a custom by Babylonian kings of decreeing, irregularly in the Babylonian case, a general cancellation of debts. Thus the Jubilee Debt campaign demands the cancellation of debts for poor countries.
Somehow it's been misappropriated by the government as a word for a anniversary on which, not the poor, but the royal rich, have huge amounts of public money spent on them.
