Ostrea gigas vs Japanese oyster

Ostrea gigas and Japanese oyster both are nouns.

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

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

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

Ostrea gigas (noun)	Japanese oyster (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