organisation vs social group

organisation and social group both are nouns.

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

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

organisation (noun)	social group (noun)
the act of organizing a business or an activity related to a business	people sharing some social relation
the activity or result of distributing or disposing persons or things properly or methodically
the act of forming or establishing something
an ordered manner; orderliness by virtue of being methodical and well organized
an organized structure for arranging or classifying
a group of people who work together
the persons (or committees or departments etc.) who make up a body for the purpose of administering something