crustacean

American  

[kruh-stay-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

With a leg span of up to one metre and a body weight of more than 4kg, they are also the world's largest land-dwelling crustacean and are able to climb trees.

From BBC ● Oct. 12, 2026

Developers have embraced the crustacean and he has become a mascot for Claude Code.

From The Wall Street Journal ● Oct. 2, 2026

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

From Science Daily ● Aug. 27, 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

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

Jellyfish, worms and crustaceans are among the community of creatures living off the huge spread of carcasses.

From BBC ● Jun. 10, 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

The job Jonas has is about as far away from the crustaceans as Earth is from Mars.

From The Wall Street Journal ● Jan. 23, 2026

When the fish are frozen out, they’ll eat other things, including crustaceans, mice, voles and small birds.

From "The Sense of Style" by Steven Pinker

Related Words

• shellfish