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

Ora King salmon crudo was dressed in passionfruit aguachile with Tabasco oil, while a uni carbonara used creamy sea urchin in place of guanciale, finished with smoked trout roe.

From Salon ● Feb. 2, 2026

When sea urchin populations grow too large, however, especially if their natural predators are heavily hunted or overfished, the balance can flip.

From Science Daily ● Dec. 12, 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

Thicknesse had fallen to the ground with tiny spikes erupting all over him; he seemed to be turning into some form of sea urchin.

From "Harry Potter and the Deathly Hallows" by J.K. Rowling