sea urchin

American

noun

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.
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.

sea urchin British

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of sea urchin

First recorded in 1585–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Crinoids are part of the phylum Echinodermata which also boasts sea urchins and sea cucumbers.

From BBC

“They have a rare species of sea urchin that you find nowhere else in the Archipelago. The spines are a foot long, and they turn red in the presence of predators.”

From Literature

Her fossilized sea urchin, from a beach on the Red Sea, “responds by radiating its own inner joy at being found and loved too,” whispering: “We are two cyclical beings, each with their own story.”

From The Wall Street Journal

In turn, sea urchins are an important food source for many marine mammals, fish, crustaceans, and sea stars.

From Science Daily

The robot plucked sea stars and sea urchins and sea snails from the water and dropped them into rock pools along the shore.

From Literature

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023