sabbat

Any of several holidays, usually four or eight in number, in Wicca and related Neopagan religious traditions.

See Sabbath.

In mediæval demonology, the nocturnal assembly in which demons and sorcerers were thought to celebrate their orgies.

witches’ Sabbath

a midnight meeting of witches to practice witchcraft and sorcery; in the Middle Ages it was supposed to be a demonic orgy