Lesser Sunda Islands vs archipelago

Lesser Sunda Islands and archipelago both are nouns.

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

Lesser Sunda Islands (noun)	archipelago (noun)
a chain of islands forming a province of Indonesia to the east of Java; includes Bali and Timor	a group of many islands in a large body of water