Abudefduf saxatilis vs sergeant major

Abudefduf saxatilis and sergeant major both are nouns.

Word	Noun	Adjective	Verb	Adverb
Abudefduf saxatilis	Yes	No	No	No
sergeant major	Yes	No	No	No

As nouns, Abudefduf saxatilis and sergeant major are synonyms defined as:

Abudefduf saxatilis and sergeant major: large blue-grey black-striped damselfish; nearly worldwide

Abudefduf saxatilis (noun)	sergeant major (noun)
large blue-grey black-striped damselfish; nearly worldwide	large blue-grey black-striped damselfish; nearly worldwide
	a noncommissioned officer serving as chief administrative officer of a headquarters unit of the Army