ethnos vs grouping

ethnos and grouping both are nouns.

Word	Noun	Adjective	Verb	Adverb
ethnos	Yes	No	No	No
grouping	Yes	No	No	No

As nouns, grouping is a hypernym of ethnos; that is, grouping is a word with a broader meaning than ethnos:

ethnos: people of the same race or nationality who share a distinctive culture
grouping: any number of entities (members) considered as a unit

Other hypernyms of ethnos include group.

ethnos (noun)	grouping (noun)
people of the same race or nationality who share a distinctive culture	any number of entities (members) considered as a unit
	the activity of putting things together in groups
	a system for classifying things into groups