sat·ur·na·li·a 
(săt′ər-nālē-ə, -nālyə)
(săt′ər-nālē-ə, -nālyə)pl.n.
1. Saturnalia The ancient Roman seven-day festival of Saturn, which began on December 17.
2. (used with a sing. verb) A celebration marked by unrestrained revelry and often licentiousness; an orgy.
[Latin Sāturnālia, from neuter pl. of Sāturnālis, Saturnian, from Sāturnus, Saturn; see SATURN.]