Troy vs Ilion

Troy and Ilion both are nouns.

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

As nouns, Troy and Ilion are synonyms defined as:

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

Other synonyms of Troy include Ilium.

Troy (noun)	Ilion (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