Walpurgis night
Concise Oxford English Dictionary © 2008 Oxford University Press:
Walpurgis night /valˈpʊəgɪs/
▶noun (in German folklore) the night of April 30 (May Day's eve), when witches meet on the Brocken mountain and hold revels with the Devil.
– origin from Ger. Walpurgisnacht: named after St Walburga, whose feast day coincided with an ancient pagan festival.
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