brother vs friend

brother and friend both are nouns.

Word	Noun	Adjective	Verb	Adverb
brother	Yes	No	No	No
friend	Yes	No	No	No

As nouns, friend is a hypernym of brother; that is, friend is a word with a broader meaning than brother:

As nouns, friend is a hypernym of brother; that is, friend is a word with a broader meaning than brother:

brother: used as a term of address for those male persons engaged in the same movement
friend: a person you know well and regard with affection and trust

brother (noun)	friend (noun)
a male with the same parents as someone else	a person you know well and regard with affection and trust
a male person who is a fellow member (of a fraternity or religion or other group)	a person with whom you are acquainted
a close friend who accompanies his buddies in their activities	an associate who provides cooperation or assistance
used as a term of address for those male persons engaged in the same movement	a person who backs a politician or a team etc.