first balcony vs mezzanine

first balcony and mezzanine both are nouns.

Word	Noun	Adjective	Verb	Adverb
first balcony	Yes	No	No	No
mezzanine	Yes	No	No	No

As nouns, first balcony and mezzanine are synonyms defined as:

first balcony (noun)	mezzanine (noun)
first or lowest balcony	intermediate floor just above the ground floor
	first or lowest balcony