a time off from work, often used for studying, writing, doing research, or traveling
—My professor will not be teaching next year. He’s taking a sabbatical to finish writing his book.

The fourth of the Ten Commandments told the Israelites to keep the sabbath holy. The sabbath was the seventh day of the week, or Saturday, and it was a special day for rest and worship. But the Lord told them that in the Promised Land they should observe a sabbath year, as well. During this seventh year, all debts were to be canceled and the land allowed to rest:

When you enter the land that I am giving you, the land must observe a Sabbath [sabbath—KJV] to the Lord. Six years you may sow your field, and six years you may prune your vineyard and gather the produce, but in the seventh year the land must have a Sabbath of complete rest—a Sabbath to the Lord. You must not sow your field or prune your vineyard. You must not gather in the aftergrowth of your harvest and you must not pick the grapes of your unpruned vines; the land must have a year of complete rest. (Leviticus 25:2-5)

At the end of seven sabbath years, God also added a “year of jubilee.” The rules for this fiftieth year were much like the sabbath year, but in addition, any land sold in the previous 49 years was to be returned to the original owner. The word jubilee comes from the Hebrew word for ram’s horn, which was blown like a trumpet on the Day of Atonement to announce the beginning of the year of jubilee. The Lord said,

You must sound loud horn blasts—in the seventh month, on the tenth day of the month, on the Day of Atonement—you must sound the horn in your entire land. So you must consecrate the fiftieth year, and you must proclaim a release in the land for all its inhabitants. That year will be your jubilee; each one of you must return to his property and each one of you must return to his clan. That fiftieth year will be your jubilee; you must not sow the land, harvest its aftergrowth, or pick the grapes of its unpruned vines. (Leviticus 25:9-11)

Today,  jubilee can be used for any anniversary or celebration.