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

Krill oil is a popular alternative to fish oil, made from tiny shrimp-like creatures (crustaceans) that feed whales and other Antarctic wildlife. —Stephanie Brown, Verywell Health, 3 Dec. 2025

The crustaceans also prey on native species, eat fish eggs, and compete with local fish and crayfish for food. —Staff Author Updated, PEOPLE, 3 Dec. 2025

Along with the crustaceans, the four-inch-diameter glass sphere contains gravel, an elegant branch of artificial coral, and algae that supply oxygen and food—the perfect houseguests ($99). —Patricia Marx, New Yorker, 22 Nov. 2025

If connectivity becomes an issue, crustaceans won’t be to blame. —Andrew Nusca, Fortune, 5 Nov. 2025

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