Korea vs Korean Peninsula

Korea and Korean Peninsula both are nouns.

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

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

Korea and Korean Peninsula: 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 Korea include Dae-Han-Min-Gook, Han-Gook.

Korea (noun)	Korean Peninsula (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