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

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

Few people know the truth about the crustacean that briefly resides in their child’s bedroom: that it was meant to live for at least 30 years.

From Slate ● Aug. 19, 2025

At present, it is allowed to cut up a crustacean alive, unlike the mammals we eat.

From Science Daily ● Nov. 26, 2024

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

On the small vessel’s deck, a pair of traps containing skittering crustaceans had just been heaved aboard from 25 feet below the water.

From The Wall Street Journal ● Jul. 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

There are also about 100 species of corals which, together with mangroves and seagrass beds, form essential breeding and nursery grounds for fish and crustaceans.

From Barron's ● Mar. 17, 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

It eats small crustaceans and will attempt to tackle larger prey.

From "Fantastic Beasts and Where to Find Them" by J.K. Rowling

Related Words

• shellfish