arachnid

詳細解釋：

a.rach.nid

n.（名詞）
Any of various arthropods of the class Arachnida, such as spiders, scorpions, mites, and ticks, characterized by four pairs of segmented legs and a body that is divided into two regions, the cephalothorax and the abdomen.Also called arachnoid
蜘蛛綱動物：一種蜘蛛綱節肢動物們，如蜘蛛、蠍子、小蟲及扁虱，特徵是有四對分節的腿和分為兩部分即頭胸部及腹部的身體也作 arachnoid

來源：
From New Latin Arachnida [class name]
源自 現代拉丁語 Arachnida [綱名]
from Greek arakhnô [spider]
源自 希臘語 arakhnô [蜘蛛]

【引伸】
arach.nidan