Western Isles vs Hebridean Islands

Western Isles and Hebridean Islands both are nouns.

Word	Noun	Adjective	Verb	Adverb
Western Isles	Yes	No	No	No
Hebridean Islands	Yes	No	No	No

As nouns, Western Isles and Hebridean Islands are synonyms defined as:

Western Isles and Hebridean Islands: a group of more than 500 islands off the western coast of Scotland

Other synonyms of Western Isles include Hebridean Isles, Hebrides, Western Islands.

Western Isles (noun)	Hebridean Islands (noun)
a group of more than 500 islands off the western coast of Scotland	a group of more than 500 islands off the western coast of Scotland