sea-urchin

A child carefully picks up a sea-urchin from a tide pool.

Definition

1. Noun:
   • A marine animal: a "sea-urchin" is a small, spiny, round or oval-shaped marine invertebrate belonging to the class Echinoidea. It has a hard shell (test) covered in movable spines and is found on the ocean floor.

Usage Examples

• Noun:
  • The sea-urchin uses its spines to protect itself from predators. (The animal defends itself with its sharp spines.)
  • Divers often find sea-urchins hiding among rocks in shallow waters. (These creatures are commonly seen in coastal areas.)
  • A sea-urchin's mouth, called Aristotle's lantern, is located on its underside. (The feeding structure is a distinctive feature.)

Advanced Usage

• "sea-urchin roe": the edible reproductive organs (gonads) of the sea-urchin, considered a delicacy in many cuisines, especially Japanese (uni) and Mediterranean.
  • The chef served fresh sea-urchin roe on a bed of rice. (The gonads were prepared as sushi.)
• "sea-urchin barren": an area of ocean floor where overgrazing by sea-urchins has destroyed kelp forests, leaving a barren landscape.
  • Overpopulation of sea-urchins has created a sea-urchin barren along the coast. (The kelp ecosystem has collapsed.)

Variants and Related Words

• Sea-urchin-like (adj): resembling a sea-urchin in shape or texture.
  • The cactus had a sea-urchin-like appearance with its round body and spines. (It looked similar to the marine animal.)
• Urchin (n): a shortened form sometimes used in informal contexts, though "urchin" alone usually refers to a mischievous child.
  • The tide pool was full of small urchins. (Here, "urchins" means sea-urchins.)

Synonyms

• Echinoid: the scientific term for a member of the class Echinoidea, to which sea-urchins belong.
  • Echinoids have been studied for their unique locomotion system. (This is a formal synonym.)
• Sea hedgehog: an older or alternative common name for the sea-urchin, referring to its spiny appearance.
  • In some regions, the sea-urchin is called a sea hedgehog. (This name is less common today.)

Phrasal Verbs

• No common phrasal verbs exist for "sea-urchin", as it is a noun referring to a specific animal. However, the verb "to urchin" is not standard.

Related Idioms

• No common idioms exist specifically for "sea-urchin". The word is primarily used in marine biology, cooking, and ecology contexts.