hay·​stack | \ˈhā-ˌstak \

Definition of haystack 

1 : a stack of hay

2 : a vertical standing wave in turbulent river waters

Examples of haystack in a Sentence

Recent Examples on the Web

Finding meteor fragments scattered on the seafloor might seem like trying to find a needle in a haystack, but the scientists participating in this hunt have a few advantages. Avery Thompson, Popular Mechanics, "Scientists Are Hunting for Meteorite Fragments Off the Coast of Washington," 3 July 2018 Finding the needle in a haystack All told, sepsis is the most costly condition treated in U.S. hospitals, affecting one in three patients who die while hospitalized. Ian Haydon, Philly.com, "Working to save lives, Philly physicians find way to help patients confront death," 26 June 2018 Toney Armstrong: That's the needle in the haystack. Josh Gelman, CBS News, "New twist in probe of slain NBA star Lorenzen Wright," 12 May 2018 Rather than stimulating the production of as many eggs as possible to find the proverbial needle in the haystack, Dr. Oxana sought to gently stimulate the production of only a handful of eggs, hoping to find one or two good ones. Elizabeth Katkin, Marie Claire, "It Took 7 Miscarriages, 10 IVF cycles, 9 Years, and Nearly $200,000 to Solve My Fertility Issues," 15 June 2018 Smartphones, web browsers and sensors provide huge quantities of information that governments can hack or collect; data centres allow them to store it indefinitely; AI helps them find needles in the digital haystacks thus assembled. The Economist, "Does China’s digital police state have echoes in the West?," 31 May 2018 Finding a needle in a haystack, like going to a show and seeing something nobody else has seen, is really rare. Melinda Newman, Billboard, "Warner Music Nashville A&R Cris Lacy On Signing Kenny Chesney, Competition In Nashville & More," 5 June 2018 The needle that emerged from this haystack of demands was the same set of NOTCH2NLs that Dr Haussler’s team had lit upon. The Economist, "A history of big-headedness," 31 May 2018 That means finding the right place to block a vulnerable site that doesn’t change is effectively a needle-in-a-haystack challenge. Bradley J. Fikes, sandiegouniontribune.com, "By luck, Scripps Research scientists find clue to a powerful new class of flu drugs," 2 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'haystack.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of haystack

15th century, in the meaning defined at sense 1

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Dictionary Entries near haystack





hay sweep



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Time Traveler for haystack

The first known use of haystack was in the 15th century

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More Definitions for haystack



English Language Learners Definition of haystack

: a large pile of hay


hay·​stack | \ˈhā-ˌstak \

Kids Definition of haystack

: a large pile of hay stored outdoors

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a private place of worship

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