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

This is where the species spend their productive summer months, feasting on small crustaceans and other seafloor prey. —Scott Travers, Forbes.com, 26 Jan. 2026

They're classified as hexapods and are more closely related to crustaceans rather than insects, despite their appearance. —Cailey Gleeson, jsonline.com, 23 Jan. 2026

Krill are tiny crustaceans resembling shrimp that live in the open ocean. —Bestreviews, Chicago Tribune, 7 Jan. 2026

There was plenty of fajita seasoning to coat every crustacean, and the tacos were fully-loaded. —Lizzy Briskin, Bon Appetit Magazine, 22 Dec. 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