Union of Burma vs Myanmar

Union of Burma and Myanmar both are nouns.

Word	Noun	Adjective	Verb	Adverb
Union of Burma	Yes	No	No	No
Myanmar	Yes	No	No	No

As nouns, Union of Burma and Myanmar are synonyms defined as:

Union of Burma and Myanmar: a mountainous republic in southeastern Asia on the Bay of Bengal

Other synonyms of Union of Burma include Burma.

Union of Burma (noun)	Myanmar (noun)
a mountainous republic in southeastern Asia on the Bay of Bengal	a mountainous republic in southeastern Asia on the Bay of Bengal