Saturnalia, in ancient Rome, festival honoring Saturn, god of fertility and planting. The annual festival, which started Dec. 17, originated as a 2-day celebration of the winter planting, but became a week-long period of feasting and gift-giving, the cessation of business and a brief time of freedom for slaves. Its observances are thought to have eventually been absorbed into the celebration of Christmas. “Saturnalia” has become a generic term for any period of wild revelry.
See also: Saturn.