Osteostraci vs Cephalaspida

Osteostraci and Cephalaspida both are nouns.

Word	Noun	Adjective	Verb	Adverb
Osteostraci	Yes	No	No	No
Cephalaspida	Yes	No	No	No

As nouns, Osteostraci and Cephalaspida are synonyms defined as:

Osteostraci and Cephalaspida: extinct group of armored fish-like vertebrates; taxonomy is not clear

Other synonyms of Osteostraci include suborder Cephalaspida, suborder Osteostraci.

Osteostraci (noun)	Cephalaspida (noun)
extinct group of armored fish-like vertebrates; taxonomy is not clear	extinct group of armored fish-like vertebrates; taxonomy is not clear