merostome
/ˈmɪərəstəʊm/ /ˈmɛrəstəʊm/Zoology
noun
A chelicerate arthropod of the class Merostomata, of which the horseshoe crab is the only extant member.
Origin
Late 19th century; earliest use found in Smithsonian Institution Annual Reports. From mero- + -stome, after scientific Latin Merostomata, (former) suborder name.