Greater Sunda Islands vs archipelago

Greater Sunda Islands and archipelago both are nouns.

Word	Noun	Adjective	Verb	Adverb
Greater Sunda Islands	Yes	No	No	No
archipelago	Yes	No	No	No

Greater Sunda Islands (noun)	archipelago (noun)
a chain of islands including Borneo and Celebes and Java and Sumatra	a group of many islands in a large body of water