pin·​worm ˈpin-ˌwərm How to pronounce pinworm (audio)
: any of numerous small nematode worms (family Oxyuridae) that infest the intestines and especially the cecum of various vertebrates
especially : a worm (Enterobius vermicularis) parasitic in humans
: any of several rather slender insect larvae that burrow in plant tissue

Example Sentences

Recent Examples on the Web That analysis revealed the presence of parasitic eggs from four different species: whipworm, beef/pork tapeworm, roundworm, and pinworm. Jennifer Ouellette, Ars Technica, 11 Feb. 2022 And then there's the most common worm infection in the U.S.: pinworm. Casey Gueren, SELF, 19 Aug. 2021 Linda tries to take her family to the symphony on free-admission night, but her efforts are thwarted by a pinworm epidemic. Washington Post, 3 Oct. 2020 The presence of specific parasites can also indicate whether a sample is human or canine, such as eggs from pinworms (Enterobius vermicularis), which are typically only present in human feces. Jennifer Ouellette, Ars Technica, 19 Apr. 2020 Further testing showed that all four had anti-cancer effects, but one in particular, pyrvinium pamoate, which is approved for the treatment of pinworms, significantly reduced the growth of liver-cancer tumors in laboratory mice. Aimee Swartz, Washington Post, 13 May 2018 The lab mice would pick up whatever the pet-shop mouse was carrying—everything from fur mites and pinworms to mouse hepatitis—and perhaps become immunologically more like the pet-shop mouse. Cassandra Willyard, Scientific American, 9 Apr. 2018 Pests monitored: Pheromone lures are available for diamondback moths and moths that produce armyworms, cabbage loopers, corn earworms, European corn borers, tomato pinworms, and cutworms. The Editors Of Organic Life, Good Housekeeping, 18 Dec. 2017 Luckily, pinworm infections don't usually lead to any complications. Samantha Lauriello,, 3 July 2019 See More

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

Word History

First Known Use

1846, in the meaning defined at sense 1

Time Traveler
The first known use of pinworm was in 1846

Dictionary Entries Near pinworm

Cite this Entry

“Pinworm.” Dictionary, Merriam-Webster, Accessed 6 Dec. 2022.

Kids Definition



pin·​worm -ˌwərm How to pronounce pinworm (audio)
: any of numerous small roundworms that infest the intestines of various vertebrates
especially : one that infests human beings

Medical Definition



pin·​worm ˈpin-ˌwərm How to pronounce pinworm (audio)
: any of numerous small nematode worms of the family Oxyuridae that have the tail of the female prolonged into a sharp point and infest the intestines and especially the cecum of various vertebrates
especially : a worm of the genus Enterobius (E. vermicularis) that is parasitic in humans

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