masses vs group

masses and group both are nouns.

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

As nouns, group is a hypernym of masses; that is, group is a word with a broader meaning than masses:

Other hypernyms of masses include grouping.

masses (noun)	group (noun)
the common people generally	any number of entities (members) considered as a unit
	a set that is closed, associative, has an identity element and every element has an inverse
	(chemistry) two or more atoms bound together as a single unit and forming part of a molecule

masses (verb)	group (verb)
	arrange into a group or groups
	form a group or group together