crustacean

American  

[kruh-stey-shuhn] / krʌˈsteɪ ʃən /

noun

• crustaceans
  plural

1. any chiefly aquatic arthropod of the class Crustacea, typically having the body covered with a hard shell or crust, including the lobsters, shrimps, crabs, barnacles, and wood lice.

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adjective

1. belonging or pertaining to the crustaceans.

crustacean British  

/ krʌˈsteɪʃən /

noun

1. any arthropod of the mainly aquatic class Crustacea, typically having a carapace hardened with lime and including the lobsters, crabs, shrimps, woodlice, barnacles, copepods, and water fleas

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adjective

1. of, relating to, or belonging to the Crustacea

crustacean Scientific  

/ krŭ-stā′shən /

1. Any of various widespread arthropods of the class Crustacea that live mostly in water and have a hard shell, a segmented body, and jointed appendages. Crustaceans include crabs, lobsters, shrimp, barnacles, and copepods.

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crustacean Cultural  

1. A class of arthropods with shells.

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Discover More

Crabs, lobsters, shrimp, and crayfish are crustaceans.

Other Word Forms

Noun Inflected Forms

• crustaceans
  plural

Etymology

Origin of crustacean

1825–35; < New Latin Crustace ( a ) (neuter plural) hard-shelled ones ( see crust, -acea) + -an

Explanation

A crustacean is a member of a class of arthropods that live in water. Some of your favorite seafood comes from crustaceans — crabs, lobsters, and shrimp. There are plenty of fish in the sea, and there are also plenty of crustaceans: strange-looking aquatic critters who usually have at least four pairs of limbs, plus a segmented body and a chitinous exoskeleton. If you think of a crust as being a little like a shell, that can help you remember crustaceans are essentially critters that have shells. Our word crust is from Latin crusta (shell or crust).

Example Sentences

See Examples For:

crustacean crustaceans

As insects evolved away from their crustacean ancestors, swimming appendages were progressively simplified and lost.

From Science Daily ● Aug. 27, 2026

Wags are calling it the “lobstermander” because the new House District 7 extends like a crustacean with the tail in heavily Democratic northern Virginia to the body stretching downstate and branching into two claws.

From The Wall Street Journal ● Apr. 22, 2026

"Since January, I've spent hours on the lobster every day," Gao told AFP, referring to OpenClaw's red crustacean mascot.

From Barron's ● Mar. 13, 2026

But he told the BBC when the express service reached its final stop "sure enough" he found the crustacean "chilling" on a seat.

From BBC ● Sep. 19, 2025

The fiddler crab, that small and picturesque crustacean whose hordes move over mud flats or sand flats like grazing cattle, has no defense against the sprayers.

From "Silent Spring" by Rachel Carson

Some specimens preserve flap-like structures on the abdomen resembling features seen in modern crustaceans such as lobsters, raising the possibility that the giant scorpion could move between water and land.

From Science Daily ● Sep. 2, 2026

They eat crustaceans, birds and fish and grow to be up to about four feet long and 32 pounds.

From Los Angeles Times ● Aug. 15, 2026

Instead, it has proven to be about Appalachian springsnails—and a few other rare or endangered species, including freshwater mussels, fish, and crustaceans.

From Slate ● Apr. 27, 2026

Grey seals typically feed on fish such as sand eels, cod and herring, as well as squid and crustaceans.

From BBC ● Mar. 2, 2026

They are linked so intimately and indispensably with the lives of many fishes, mollusks, and crustaceans that were they no longer habitable these seafoods would disappear from our tables.

From "Silent Spring" by Rachel Carson

Related Words

• shellfish