In the Bible the Jubilee (spelled "jubile" in the King James Version) is the fiftieth year, described in Leviticus 25, in which land is returned to its original families and Hebrew servants are freed.
Leviticus 25:10 in the King James Version reads:
And ye shall hallow the fiftieth year, and proclaim liberty throughout all the land unto all the inhabitants thereof: it shall be a jubile unto you; and ye shall return every man unto his possession, and ye shall return every man unto his family.
The verse appears in Leviticus 25, in the laws for the sabbath year and the year of jubile. Read it in context at Leviticus 25:10, or the full chapter at Leviticus 25. Encyclopedia entry: en.wikipedia.org/wiki/Jubilee_(biblical).