crustacean

noun

crus·​ta·​cean ˌkrə-ˈstā-shən 

: any of a large class (Crustacea) of mostly aquatic mandibulate arthropods that have a chitinous or calcareous and chitinous exoskeleton, a pair of often much modified appendages on each segment, and two pairs of antennae and that include the lobsters, shrimp, crabs, wood lice, water fleas, and barnacles

crustacean adjective

Examples of crustacean in a Sentence

Recent Examples on the Web

Emperor penguins mainly consume fish, squid and crustaceans in Antarctic waters. —ABC News, 9 Apr. 2026

Some groups died out, but others eventually gave rise to modern animal groups such as chordates, crustaceans and mollusks. —Mindy Weisberger, CNN Money, 4 Apr. 2026

But fortunately, the larvae happily fed on the tiny crustaceans called copepods that the aquarists gave them. —Ari Daniel, NPR, 31 Mar. 2026

These crustaceans, worms, fish, and others keep their home clean by grazing on the algae that encrusts seagrass leaves. —David George Haskell, Big Think, 27 Mar. 2026

Word History

First Known Use

1835, in the meaning defined above

Rhymes for crustacean

• ablation
• bination
• carnation
• cassation
• castration
• causation
• centration
• cessation
• cetacean
• chelation
• citation
• collation

Kids Definition

crustacean

noun

crus·​ta·​cean ˌkrəs-ˈtā-shən 

: any of a large class of mostly water-dwelling arthropods (as lobsters, shrimps, crabs, wood lice, water fleas, and barnacles) having an exoskeleton of chitin or chitin and a compound of calcium

crustacean adjective