Definition of horseshoe crab
: any of several closely related marine arthropods (order Xiphosura and class Merostomata) 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 —called also king crab
First Known Use of horseshoe crab
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Britannica.com: Encyclopedia article about horseshoe crab
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