sea urchin

noun

: any of numerous echinoderms (class Echinoidea) that are usually enclosed in thin brittle globular tests covered with movable spines

Examples of sea urchin in a Sentence

Recent Examples on the Web

Research on corals, sea snails, sea urchins, mussels and fish has found microplastic pollution left them less able to cope with rising ocean temperatures and ocean acidification, both fueled by climate change. —Laura Paddison, CNN Money, 27 Nov. 2025

At the helm, chef Jon Yao is leaning into his Taiwanese heritage and upbringing in Southern California’s San Gabriel Valley, serving dishes like suāncài yú, a riff on a Sichuan seafood dish with black cod and pickled mustard greens, and youtiao, a savory donut with sea urchin, ham, and caviar. —Jeremy Repanich, Robb Report, 19 Nov. 2025

Sunflower sea stars—large predators that feed on sea urchins—were particularly vulnerable, losing nearly 90 percent of their pre-pandemic population in northern waters. —JSTOR Daily, 17 Oct. 2025

Rather than direct interpretations of sea urchins and starfish, the jeweler took a sculptural and textural approach in her designs. —Sandra Salibian, Footwear News, 10 Oct. 2025

Word History

First Known Use

1591, in the meaning defined above

Kids Definition

sea urchin

noun

: any of a class of small marine invertebrate animals that are echinoderms, usually live on or burrow in the sea bottom, and are enclosed in roundish shells covered with spines that can move