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

While many of the plates highlight seafood—like in Ramirez’s truffle Hokkaido sea urchin on brioche—a couple dishes emphasize meat or game from specialty farms, such as quail from Wolfe Ranch. —Tori Latham, Robb Report, 16 July 2024

In fact, most aquatic invertebrates and all echinoderms (sea stars, sea urchins, sea cucumbers, and sand dollars) start life as planktonic larvae before growing into the adult form we’re used to seeing. —Jennifer Adler, Vox, 7 July 2024

Sunscreen can easily come off in open water and bioaccumulate, threatening fish, sea urchins, dolphins, mussels, coral and algae, according to the National Ocean Service. —Clare Mulroy, USA TODAY, 17 June 2024

What if researchers could access sea urchins as easily as mice? —Corinne Purtill, Los Angeles Times, 29 May 2024

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