Windward Islands vs Windward Isles

Windward Islands and Windward Isles both are nouns.

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

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

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

Windward Islands (noun)	Windward Isles (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