Japanese oyster vs Ostrea gigas

Japanese oyster and Ostrea gigas both are nouns.

Word	Noun	Adjective	Verb	Adverb
Japanese oyster	Yes	No	No	No
Ostrea gigas	Yes	No	No	No

As nouns, Japanese oyster and Ostrea gigas are synonyms defined as:

Japanese oyster and Ostrea gigas: a large oyster native to Japan and introduced along the Pacific coast of the United States; a candidate for introduction in Chesapeake Bay

Japanese oyster (noun)	Ostrea gigas (noun)
a large oyster native to Japan and introduced along the Pacific coast of the United States; a candidate for introduction in Chesapeake Bay	a large oyster native to Japan and introduced along the Pacific coast of the United States; a candidate for introduction in Chesapeake Bay