witches' Sabbath

The phrase is first attested in the seventeenth century, but was popularized only from the 20th century onwards. This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term. more to be said on this

witches' Sabbath (plural witches' Sabbaths)

1. A supposed meeting of witches at midnight to practice sorcery or to take part in a demonic orgy.

   Synonym: black Sabbath

2. A religious gathering of a Wiccan coven at a covenstead or circle

• sabbat