1
: a stack of hay
2
: a vertical standing wave in turbulent river waters
Examples of haystack in a Sentence
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Tomasino told me this is not necessarily a scientific claim; still, the sheer quantity of chemicals interacting in a glass gives the search for offenders a needle-in-a-haystack quality.
—
Nicola Twilley, New Yorker, 5 Jan. 2026
Researchers from the Australian Wildlife Conservancy (AWC) made this needle-in-haystack find by chance, spotting a large patch of Drosera silvicola just outside of the west coast city of Perth.
—New Atlas, 5 Dec. 2025
However, the gravitational wave detectors were only able to narrow down the source of this signal to a region of sky equivalent to around 6,000 times the width of the moon, which makes looking for an accompanying electromagnetic signal akin to searching for a needle in a cosmic haystack.
—Robert Lea, Space.com, 30 Nov. 2025
According to scientists, detecting such an event in the Large Hadron Collider data is extremely rare and as difficult as finding a single needle in a haystack the size of an Olympic stadium.
—Georgina Jedikovska, Interesting Engineering, 4 Nov. 2025
See All Example Sentences for haystack
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Nicola Twilley, New Yorker, 5 Jan. 2026
Researchers from the Australian Wildlife Conservancy (AWC) made this needle-in-haystack find by chance, spotting a large patch of Drosera silvicola just outside of the west coast city of Perth.
—New Atlas, 5 Dec. 2025
However, the gravitational wave detectors were only able to narrow down the source of this signal to a region of sky equivalent to around 6,000 times the width of the moon, which makes looking for an accompanying electromagnetic signal akin to searching for a needle in a cosmic haystack.
—Robert Lea, Space.com, 30 Nov. 2025
According to scientists, detecting such an event in the Large Hadron Collider data is extremely rare and as difficult as finding a single needle in a haystack the size of an Olympic stadium.
—Georgina Jedikovska, Interesting Engineering, 4 Nov. 2025
See All Example Sentences for haystack
Cite this Entry
“Haystack.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/haystack. Accessed 10 Jan. 2026.
Copy CitationKids Definition
haystack
noun
hay·stack
-ˌstak 
: a stack of hay
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