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

In the world of Bathynellacea crustaceans, Megabathynella totemensis is a genuine outlier — bigger, clawier, and toothier than most of its relatives. —Hanna Wickes, Charlotte Observer, 20 Feb. 2026

Scientists don’t yet fully understand why these crustaceans grow so large compared to their relatives. —Hanna Wickes, Miami Herald, 20 Feb. 2026

Read on to find out the the real story of these two crustaceans and our favorite recipes to make with them. —Susan Hall Mahon, Southern Living, 18 Feb. 2026

Crawfish The humble mudbug is Louisiana’s iconic crustacean, the source of much communal joy in spring. —Outside, 17 Feb. 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