Rostov-on-Don vs Rostov

Rostov-on-Don and Rostov both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rostov-on-Don	Yes	No	No	No
Rostov	Yes	No	No	No

As nouns, Rostov-on-Don and Rostov are synonyms defined as:

Rostov-on-Don and Rostov: a seaport on the Don River near the Sea of Azov in the European part of Russia

Other synonyms of Rostov-on-Don include Rostov na Donu, Rostov on Don.

Rostov-on-Don (noun)	Rostov (noun)
a seaport on the Don River near the Sea of Azov in the European part of Russia	a seaport on the Don River near the Sea of Azov in the European part of Russia