Anglesey Island vs Anglesea

Anglesey Island and Anglesea both are nouns.

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

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

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

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