Windward Isles vs Windward Islands

Windward Isles and Windward Islands both are nouns.

Word	Noun	Adjective	Verb	Adverb
Windward Isles	Yes	No	No	No
Windward Islands	Yes	No	No	No

As nouns, Windward Isles and Windward Islands are synonyms defined as:

Windward Isles and Windward Islands: a group of islands in the southeastern West Indies; the southern part of the Lesser Antilles

Windward Isles (noun)	Windward Islands (noun)
a group of islands in the southeastern West Indies; the southern part of the Lesser Antilles	a group of islands in the southeastern West Indies; the southern part of the Lesser Antilles