horseshoe crab

noun

: any of several closely related marine arthropods (family Limulidae and order Xiphosura) with a broad crescentic cephalothorax, six pairs of legs, and a spikelike tail

especially : one (Limulus polyphemus) of coastal waters from Maine to the Yucatán Peninsula

Note: The horseshoe crab is often said to have five pairs of legs since the first pair is greatly reduced in size and used mainly for feeding. All the legs of the horseshoe crab end in claws except for the last pair of legs which have leaflike expansions used mainly for pushing.

… a horseshoe crab … is a Swiss army knife of jointed limbs—for walking, swimming, grasping, shredding, and defending.

—Carl Zimmer

… the horseshoe crab has changed little since an ancestor was fossilized 150 million years ago …

—National Geographic

called also king crab

Examples of horseshoe crab in a Sentence

Recent Examples on the Web

The creatures — distant relatives of contemporary spiders, scorpions, and horseshoe crabs — were preserved in remarkably good shape, according to a report in Current Biology. —Paul Smaglik, Discover Magazine, 29 Oct. 2024

Interactive programming ranges from tide pools where kids can touch sea anemones, seastars, bat rays, and horseshoe crabs to daylong whale-watching excursions. —Sunset Magazine, 10 Sep. 2024

Additionally, horseshoe crabs have a reproductive strategy that includes spawning in large numbers, which increases the chances of survival of offspring despite environmental fluctuations. —Scott Travers, Forbes, 7 Sep. 2024

Instead, the sea-bug taco likely got around as modern horseshoe crabs do: by swimming upside down. —Mindy Weisberger, CNN, 30 July 2024

Word History

First Known Use

1797, in the meaning defined above

Kids Definition

horseshoe crab

noun

: any of several closely related arthropods that have a broad crescent-shaped united head and thorax and a tail resembling a spike