Ulan Bator vs Ulaanbaatar

Ulan Bator and Ulaanbaatar both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ulan Bator	Yes	No	No	No
Ulaanbaatar	Yes	No	No	No

As nouns, Ulan Bator and Ulaanbaatar are synonyms defined as:

Other synonyms of Ulan Bator include capital of Mongolia, Kulun, Urga.

Ulan Bator (noun)	Ulaanbaatar (noun)
the capital and largest city of Mongolia	the capital and largest city of Mongolia