polyplacophore vs coat-of-mail shell

polyplacophore and coat-of-mail shell both are nouns.

Word	Noun	Adjective	Verb	Adverb
polyplacophore	Yes	No	No	No
coat-of-mail shell	Yes	No	No	No

As nouns, polyplacophore and coat-of-mail shell are synonyms defined as:

polyplacophore and coat-of-mail shell: primitive elongated bilaterally symmetrical marine mollusk having a mantle covered with eight calcareous plates

Other synonyms of polyplacophore include chiton, sea cradle.

polyplacophore (noun)	coat-of-mail shell (noun)
primitive elongated bilaterally symmetrical marine mollusk having a mantle covered with eight calcareous plates	primitive elongated bilaterally symmetrical marine mollusk having a mantle covered with eight calcareous plates