The story
From sea + urchin (“hedgehog”), reflecting a similarity in appearance to a hedgehog.
Etymology from Wiktionary, CC BY-SA 4.0.
sea urchin
sea ur·chinToday it means: Any of many marine echinoderms, of the class Echinoidea, commonly found in shallow water, having a complex chewing structure named Aristotle's lantern. Full definition →