roundworm
noun
round·worm
ˈrau̇nd-ˌwərm 
: nematode
also
: a related round-bodied unsegmented worm (such as a spiny-headed worm) as distinguished from a flatworm
Examples of roundworm in a Sentence
Recent Examples on the Web
My guess is that your veterinarian was correct in assessing roundworms based on their appearance.
—
Dr. John De Jong, Boston Herald, 18 Jan. 2026
During a routine exam, veterinarians found Baylisascaris eggs in the dog’s system — the first such formal report of raccoon roundworm in a dog in county history, according to a Los Angeles County Department of Public Health news release.
—Terry Castleman, Los Angeles Times, 18 Jan. 2026
About 28 percent of the samples contained whipworm or roundworm eggs, whereas others had traces of Giardia duodenalis.
—Claire Cameron, Scientific American, 22 Dec. 2025
Scientists analyzing the sewer drains from the Roman fort Vindolanda (near Hadrian’s Wall in northern England) found three types of intestinal parasites—roundworm,whipworm, and Giardia duodenalis.
—Laura Baisas, Popular Science, 19 Dec. 2025
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Dr. John De Jong, Boston Herald, 18 Jan. 2026
During a routine exam, veterinarians found Baylisascaris eggs in the dog’s system — the first such formal report of raccoon roundworm in a dog in county history, according to a Los Angeles County Department of Public Health news release.
—Terry Castleman, Los Angeles Times, 18 Jan. 2026
About 28 percent of the samples contained whipworm or roundworm eggs, whereas others had traces of Giardia duodenalis.
—Claire Cameron, Scientific American, 22 Dec. 2025
Scientists analyzing the sewer drains from the Roman fort Vindolanda (near Hadrian’s Wall in northern England) found three types of intestinal parasites—roundworm,whipworm, and Giardia duodenalis.
—Laura Baisas, Popular Science, 19 Dec. 2025
See All Example Sentences for roundworm
Cite this Entry
“Roundworm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/roundworm. Accessed 5 Feb. 2026.
Copy CitationKids Definition
roundworm
noun
round·worm
ˈrau̇n-ˌdwərm
: a nematode worm (as a hookworm)
also
: a related round-bodied worm without segments as compared to a flatworm
Medical Definition
roundworm
noun
round·worm
ˈrau̇n-ˌdwərm
: nematode
also
: a related round-bodied unsegmented worm (as an acanthocephalan) as distinguished from a flatworm
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