trilobite (n.)youdaoicibaDictYouDict[trilobite 词源字典]
extinct marine arthropod, 1820, from Modern Latin Trilobites (Walch, 1771), from Greek tri- "three" (see three) + lobos "lobe" (see lobe); so called because its body is divided into three lobes.[trilobite etymology, trilobite origin, 英语词源]