Pacific Ocean vs Seto Inland Sea

Pacific Ocean and Seto Inland Sea both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pacific Ocean	Yes	No	No	No
Seto Inland Sea	Yes	No	No	No

Pacific Ocean (noun)	Seto Inland Sea (noun)
the largest ocean in the world	an arm of the Pacific Ocean in southern Japan; surrounded by the islands of Honshu and Shikoku and Kyushu and linked to the Sea of Japan by a narrow channel; the chief port is Hiroshima