sab·bat /ˈsæbət/
  Sab·bat n.  In mediaeval demonology, the nocturnal assembly in which demons and sorcerers were thought to celebrate their orgies.
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  sabbat
       n : a midnight meeting of witches to practice witchcraft and
           sorcery; in the Middle Ages it was supposed to be a
           demonic orgy [syn: witches' Sabbath]