Merriam-Webster's Collegiate® Dictionary, 11th Edition
SABBATICAL
I. adjective or sabbatic
Etymology: Late Latin sabbaticus, from Greek sabbatikos, from sabbaton
Date: 1599
of or relating to a sabbatical year, of or relating to the sabbath ,
II. noun
Date: 1903
sabbatical year 2, leave 1b, a break or change from a normal routine (as of employment)