Definition of sea urchin in English:

sea urchin

Line breaks: sea ur¦chin


  • A marine echinoderm which has a spherical or flattened shell covered in mobile spines, with a mouth on the underside and calcareous jaws.
    • Class Echinoidea
    More example sentences
    • The sea urchin is one of the few marine organisms whose genome has been sequenced.
    • The inner shell of a sea urchin is a hollow globe, scored in five curved sections that taper at the ends into a small hole at the top and bottom.
    • The red sea urchin's body is domed above and flat below.

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Word of the day coloratura
Pronunciation: ˌkɒlərəˈtjʊərə
elaborate ornamentation of a vocal melody