Etymology
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Waldorf salad 
1911, from Waldorf-Astoria Hotel in New York, where it first was served.
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Walpurgis night 

1820, from German Walpurgisnacht, witches' revel, especially on the Brocken in the Harz Mountains, on May-day eve, literally "the night of (St.) Walpurgis," from Walburga, English abbess who migrated to Heidenheim, Germany, and died there c. 780; May 1 being the day of the removal of her bones from Heidenheim to Eichstädt.

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Wall Street (n.)
"U.S. financial world," 1836, from street in New York City that is home to many investment firms and stock traders, as well as NYSE. The street so called because it ran along the interior of the defensive wall of the old Dutch colonial town.
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