platoon vs social group

platoon and social group both are nouns.

Word	Noun	Adjective	Verb	Adverb
platoon	Yes	No	No	No
social group	Yes	No	No	No

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

platoon (noun)	social group (noun)
a military unit that is a subdivision of a company; usually has a headquarters and two or more squads; usually commanded by a lieutenant	people sharing some social relation
a team of policemen working under the military platoon system
a group of persons who are engaged in a common activity