Ilion vs Troy

Ilion and Troy both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ilion	Yes	No	No	No
Troy	Yes	No	No	No

As nouns, Ilion and Troy are synonyms defined as:

Ilion and Troy: an ancient city in Asia Minor that was the site of the Trojan War

Other synonyms of Ilion include Ilium.

Ilion (noun)	Troy (noun)
an ancient city in Asia Minor that was the site of the Trojan War	an ancient city in Asia Minor that was the site of the Trojan War