trilobite vs arthropod

trilobite and arthropod both are nouns.

Word	Noun	Adjective	Verb	Adverb
trilobite	Yes	No	No	No
arthropod	Yes	No	No	No

As nouns, arthropod is a hypernym of trilobite; that is, arthropod is a word with a broader meaning than trilobite:

trilobite: an extinct arthropod that was abundant in Paleozoic times; had an exoskeleton divided into three parts
arthropod: invertebrate having jointed limbs and a segmented body with an exoskeleton made of chitin

trilobite (noun)	arthropod (noun)
an extinct arthropod that was abundant in Paleozoic times; had an exoskeleton divided into three parts	invertebrate having jointed limbs and a segmented body with an exoskeleton made of chitin