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.
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How to use sea urchin in a sentence
About the only things left in these empty zones are sea urchins.Urchin takeover underlies California’s vanishing kelp forests | Anushree Dave | May 7, 2021 | Science News For Students
Most significantly, the demise of important predators such as otters and sea stars has led to an explosion in the population of sea urchins, which eat kelp.Humanity’s greatest ally against climate change is the Earth itself | Sarah Kaplan | April 22, 2021 | Washington Post
Our thinking has been shaped by a few well-studied organisms and genes, like worms, flies and sea urchins.
As its growth slowed in the warmer water, less kelp drifted into the crevices of the reefs where sea urchins typically lurk.How kelp forests off California are responding to an urchin takeover | Anushree Dave | March 29, 2021 | Science News
Like the barrens farther south, the remaining forests are now covered by purple sea urchins.How kelp forests off California are responding to an urchin takeover | Anushree Dave | March 29, 2021 | Science News
I had everything from raw hamachi with sea urchin to lamb tongue.
In the indentations, sheltered from the winds, could be traced the little perforations made by the sea-urchin.Toilers of the Sea | Victor Hugo
The Sea-urchin can walk by moving its spines, tilting its body along from one place to another on the bed of the sea.
There is a great deal more to know about Five-fingers; and the Sea-urchin still has his secrets which no one can explain.
Another cousin of the Starfish is the Sea-urchin, a round prickly creature rather like the burr of the sweet-chestnut tree.
Why was it not possible to prove this fact for the eggs of the sea urchin?The Organism as a Whole | Jacques Loeb
British Dictionary definitions for sea urchin
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