Anglesey vs Anglesea Island

Anglesey and Anglesea Island both are nouns.

Word	Noun	Adjective	Verb	Adverb
Anglesey	Yes	No	No	No
Anglesea Island	Yes	No	No	No

As nouns, Anglesey and Anglesea Island are synonyms defined as:

Other synonyms of Anglesey include Anglesea, Anglesey Island, Mona.

Anglesey (noun)	Anglesea Island (noun)
an island to the northwest of Wales	an island to the northwest of Wales