Korean Peninsula vs Korea

Korean Peninsula and Korea both are nouns.

Word	Noun	Adjective	Verb	Adverb
Korean Peninsula	Yes	No	No	No
Korea	Yes	No	No	No

As nouns, Korean Peninsula and Korea are synonyms defined as:

Korean Peninsula and Korea: an Asian peninsula (off Manchuria) separating the Yellow Sea and the Sea of Japan; the Korean name is Dae-Han-Min-Gook or Han-Gook

Other synonyms of Korean Peninsula include Dae-Han-Min-Gook, Han-Gook.

Korean Peninsula (noun)	Korea (noun)
an Asian peninsula (off Manchuria) separating the Yellow Sea and the Sea of Japan; the Korean name is Dae-Han-Min-Gook or Han-Gook	an Asian peninsula (off Manchuria) separating the Yellow Sea and the Sea of Japan; the Korean name is Dae-Han-Min-Gook or Han-Gook