sea urchin(redirected from Sea urchins)
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Any of various echinoderms of the class Echinoidea, having a soft body enclosed in a rounded, radially symmetrical, calcareous skeleton covered with long spines.
(Animals) 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
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.
Any of various invertebrate sea animals having a round body covered by a shell with movable spines. Sea urchins are related to starfish.
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|Noun||1.||sea urchin - shallow-water echinoderms having soft bodies enclosed in thin spiny globular shells|
echinoderm - marine invertebrates with tube feet and five-part radially symmetrical bodies
sand dollar - flattened disklike sea urchins that live on sandy bottoms
heart urchin - sea urchin having a heart-shaped body in a rigid spiny shell