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

The kinds of intestinal worms that dogs can get are most commonly roundworm, hookworm, whipworm, and tapeworm. — Dr. John De Jong, Boston Herald, 18 Jan. 2026

This microscopic roundworm lays its eggs in root tissues, causing swellings or galls to develop on infected roots. — Kim Toscano, Southern Living, 21 June 2026

In 2024, two children in the South Bay were infected with raccoon roundworm. — Amy Corral, CBS News, 4 Mar. 2026

Nematodes are microscopic, thread-like roundworms that naturally inhabit the soil and serve as an effective organic pest control. — Sj McShane, Martha Stewart, 11 June 2026

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