masses vs mass

masses and mass both are nouns.

Word	Noun	Adjective	Verb	Adverb
masses	Yes	No	No	No
mass	Yes	Yes	Yes	No

As nouns, masses and mass are synonyms defined as:

Other synonyms of masses include hoi polloi, multitude, people, the great unwashed.

masses (noun)	mass (noun)
the common people generally	the property of a body that causes it to have weight in a gravitational field
	the property of something that is great in magnitude
	the common people generally
	an ill-structured collection of similar things (objects or people)
	a body of matter without definite shape
	(often followed by `of') a large number or amount or extent

masses (adjective)	mass (adjective)
	formed of separate units gathered into a mass or whole

masses (verb)	mass (verb)
	join together into a mass or collect or form a mass