crustacean

IPA/krʌˈsteɪʃn/
KK[krəstˈeʃən]IPA/krʌˈsteɪʃn/

crustacean — noun

  • crustaceansingular
  • crustaceansplural

1. An animal whose body is split into segments and protected by a hard outer casing

1.nounB2
Definition

An animal whose body is split into segments and protected by a hard outer casing, found mainly in aquatic environments. Familiar types include crabs, lobsters, shrimp, and barnacles.

Example

Ari found a small crustacean hiding under a rock by the beach.

Theo's biology class watched a crustacean grow a new shell after shedding its old one.

pattern: watch + crustacean + infinitive

Common collocations
  • marine crustacean
  • freshwater crustacean
  • edible crustacean
  • crustacean species
  • crustacean shell
Synonyms
  • shellfish

    broader everyday term that includes molluscs (clams, oysters) as well as crustaceans

Grammar Patterns

countable noun

plural form: crustaceans

Usage Note

Often used in the plural form 'crustaceans' when referring to the group as a whole ('most crustaceans live in salt water').

Synonym discussion

Sense: noun/1

These four terms describe related but different animal groups. 'Crustacean' is a scientific term for animals with a hard segmented shell and jointed legs, such as crabs, lobsters, and shrimp. 'Shellfish' is a broader everyday word that includes both crustaceans and molluscs — you might order 'shellfish' at a restaurant. 'Mollusc' refers to soft-bodied animals that often have a single shell, such as clams and snails. 'Arthropod' is the widest category, covering crustaceans, insects, spiders, and centipedes. A marine biologist would say 'crustacean' when describing a crab's anatomy, but a chef would say 'shellfish' when listing ingredients.

shellfish ↗molluscarthropod

Common collocations

Nouns

Prepositions

Etymology

LatinFrenchEnglish

From Latin 'crustaceus', meaning 'having a hard shell', from 'crusta' (shell or crust). The term came into English through French 'crustacé' in the early 1800s as a scientific classification for this group of animals.