adjective 1.belonging or pertaining to the order Xiphosura, comprising the horseshoe crabs.
noun 2.an arthropod of the order Xiphosura; a horseshoe
crab.
Origin: 1830–40; <
Neo-Latin Xiphosur(
a) order name (irregular <
Greek xíphos sword +
-oura, neuter plural of
-ouros -tailed, derivative of
ourá tail) +
-an