open-air marketplace vs market square

open-air marketplace and market square both are nouns.

Word	Noun	Adjective	Verb	Adverb
open-air marketplace	Yes	No	No	No
market square	Yes	No	No	No

As nouns, open-air marketplace and market square are synonyms defined as:

open-air marketplace and market square: a public marketplace where food and merchandise is sold

Other synonyms of open-air marketplace include open-air market.

open-air marketplace (noun)	market square (noun)
a public marketplace where food and merchandise is sold	a public marketplace where food and merchandise is sold