Japan vs Shikoku

Japan and Shikoku both are nouns.

Word	Noun	Adjective	Verb	Adverb
Japan	Yes	No	No	No
Shikoku	Yes	No	No	No

Japan (noun)	Shikoku (noun)
a constitutional monarchy occupying the Japanese Archipelago; a world leader in electronics and automobile manufacture and ship building	the smallest of the four main islands of Japan; to the south of Honshu and to the east of Kyushu; separated from Honshu by the Inland Sea; forested and mountainous
a string of more than 3,000 islands to the east of Asia extending 1,300 miles between the Sea of Japan and the western Pacific Ocean