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

Common types include tapeworms, roundworms, and hookworms.3 Protozoa: These parasites are single-celled and commonly infect humans through mosquitoes. —Jenna Anderson, Health, 8 Aug. 2025

People are encouraged to avoid raccoons in the wild as they are known to be defensive fighters and carry diseases, such as rabies, roundworm and leptospirosis. —Raven Brunner, People.com, 29 July 2025

In developing some of the neural net models that are most promising today, researchers were inspired by the primitive visual capabilities of a roundworm called C elegans, which famously led to the development of some kinds of AI and medical research. —John Werner, Forbes.com, 2 July 2025

This microscopic roundworm lays its eggs in root tissues, causing swellings or galls to develop on infected roots. —Kim Toscano, Southern Living, 9 July 2025

Word History

First Known Use

1558, in the meaning defined above

Kids 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