sea urchin

American  

noun

sea urchins plural

1. any echinoderm of the class Echinoidea, having a somewhat globular or discoid form, and a shell composed of many calcareous plates covered with projecting spines.

2. a tall evergreen shrub or small tree, Hakea laurina, of Australia, having narrow leaves and dense, globe-shaped clusters of crimson flowers with long yellow stamens.

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sea urchin British  

noun

1. any echinoderm of the class Echinoidea, such as Echinus esculentus ( edible sea urchin ), typically having a globular body enclosed in a rigid spiny test and occurring in shallow marine waters

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Other Word Forms

Noun Inflected Forms

• sea urchins
  plural

Etymology

Origin of sea urchin

First recorded in 1585–95

Example Sentences

See Examples For:

sea urchin

Yama Seafood Uni – The first time I tried uni — sea urchin — was at Shiro’s in Seattle.

From Salon ● Dec. 4, 2025

Visitors to Puglia, a major producer of durum wheat, can try handmade pastas in a variety of shapes, paired with broccoli rabe, sea urchin and even a horse ragù.

From The Wall Street Journal ● Oct. 27, 2025

Not to mention, you could step on a stingray or a sea urchin.

From Los Angeles Times ● Oct. 16, 2024

When Omri Bronstein began to trace the advance of a mysterious sea urchin plague down the Gulf of Aqaba in early 2023, he was ahead of the tide.

From Science Magazine ● May 28, 2024

She read the pages about the sea urchin, the horseshoe crab, and the moon snail.

From "The Line Tender" by Kate Allen