Definition from Wiktionary, the free dictionary
See also Sabbatical
From Ancient Greek σαββατικός (sabbatikos).
Alternative forms 
sabbatical (not comparable)
relating to the Sabbath
relating to an extended period of leave
sabbatical (plural sabbaticals)
- An extended period of leave, often one year long, taken by an employee in order to carry out projects not otherwise associated with the employee's job. During the sabbatical, the employer may pay some or all of the wages that would have been otherwise earned or some or all of the expenses incurred. University lecturers, for example, may be granted a one-year paid sabbatical once every seven years.
extended period of leave