Aachen vs Aix-la-Chapelle

Aachen and Aix-la-Chapelle both are nouns.

Word	Noun	Adjective	Verb	Adverb
Aachen	Yes	No	No	No
Aix-la-Chapelle	Yes	No	No	No

As nouns, Aachen and Aix-la-Chapelle are synonyms defined as:

Aachen and Aix-la-Chapelle: a city in western Germany near the Dutch and Belgian borders; formerly it was Charlemagne's northern capital

Other synonyms of Aachen include Aken.

Aachen (noun)	Aix-la-Chapelle (noun)
a city in western Germany near the Dutch and Belgian borders; formerly it was Charlemagne's northern capital	a city in western Germany near the Dutch and Belgian borders; formerly it was Charlemagne's northern capital