sea urchin

noun

Definition of sea urchin

:any of numerous echinoderms (class Echinoidea) that are usually enclosed in thin brittle globular tests covered with movable spines

First Known Use of sea urchin

1591


SEA URCHIN Defined for English Language Learners

sea urchin

noun

Definition of sea urchin for English Language Learners

  • : a small sea animal that lives on the ocean floor and is covered in sharp spines


SEA URCHIN Defined for Kids

sea urchin

noun

Definition of sea urchin for Students

:a small sea animal that is related to the starfish, lives on the sea bottom, and is enclosed in a roundish shell covered with spines that can move

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